Include chart binaries. (#2667)

Rename the plugins to be the production names

.azure/azure-pipelines.yml

@@ -71,7 +71,7 @@ steps:
   - bash: RUSTFLAGS="-D warnings" cargo clippy --all -- -D clippy::unwrap_used
     condition: eq(variables['style'], 'canary')
     displayName: Check clippy lints
-  - bash: RUSTFLAGS="-D warnings" cargo test --all --no-default-features
+  - bash: RUSTFLAGS="-D warnings" cargo test --all --no-default-features --features=rustyline-support
     condition: eq(variables['style'], 'minimal')
     displayName: Run tests
   - bash: RUSTFLAGS="-D warnings" cargo test --all --features=extra

.cargo/config.toml

@@ -0,0 +1,6 @@
+# use LLD as linker on Windows because it could be faster
+# for full and incremental builds compared to default
+
+[target.x86_64-pc-windows-msvc]
+#linker = "lld-link.exe"
+rustflags = ["-C", "link-args=-stack:10000000"]

CONTRIBUTING.md

@@ -31,6 +31,11 @@ cargo build
   cargo build --release && cargo run --release
   ```
 
+- Build and run with extra features:
+  ```shell
+  cargo build --release --features=extra && cargo run --release --features=extra
+  ```
+
 - Run Clippy on Nushell:
 
   ```shell
@@ -60,3 +65,11 @@ cargo build
   ```shell
   cargo fmt --all
   ```
+
+### Debugging Tips
+
+- To view verbose logs when developing, enable the `trace` log level.
+
+  ```shell
+  cargo build --release --features=extra && cargo run --release --features=extra -- --loglevel trace
+  ```

Cargo.toml

@@ -10,7 +10,7 @@ license = "MIT"
 name = "nu"
 readme = "README.md"
 repository = "https://github.com/nushell/nushell"
-version = "0.19.0"
+version = "0.21.0"
 
 [workspace]
 members = ["crates/*/"]
@@ -18,51 +18,57 @@ members = ["crates/*/"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-nu-cli = {version = "0.19.0", path = "./crates/nu-cli"}
-nu-data = {version = "0.19.0", path = "./crates/nu-data"}
-nu-errors = {version = "0.19.0", path = "./crates/nu-errors"}
-nu-parser = {version = "0.19.0", path = "./crates/nu-parser"}
-nu-plugin = {version = "0.19.0", path = "./crates/nu-plugin"}
-nu-protocol = {version = "0.19.0", path = "./crates/nu-protocol"}
-nu-source = {version = "0.19.0", path = "./crates/nu-source"}
-nu-value-ext = {version = "0.19.0", path = "./crates/nu-value-ext"}
+nu-cli = {version = "0.21.0", path = "./crates/nu-cli"}
+nu-data = {version = "0.21.0", path = "./crates/nu-data"}
+nu-errors = {version = "0.21.0", path = "./crates/nu-errors"}
+nu-parser = {version = "0.21.0", path = "./crates/nu-parser"}
+nu-plugin = {version = "0.21.0", path = "./crates/nu-plugin"}
+nu-protocol = {version = "0.21.0", path = "./crates/nu-protocol"}
+nu-source = {version = "0.21.0", path = "./crates/nu-source"}
+nu-value-ext = {version = "0.21.0", path = "./crates/nu-value-ext"}
 
-nu_plugin_binaryview = {version = "0.19.0", path = "./crates/nu_plugin_binaryview", optional = true}
-nu_plugin_fetch = {version = "0.19.0", path = "./crates/nu_plugin_fetch", optional = true}
-nu_plugin_from_bson = {version = "0.19.0", path = "./crates/nu_plugin_from_bson", optional = true}
-nu_plugin_from_sqlite = {version = "0.19.0", path = "./crates/nu_plugin_from_sqlite", optional = true}
-nu_plugin_inc = {version = "0.19.0", path = "./crates/nu_plugin_inc", optional = true}
-nu_plugin_match = {version = "0.19.0", path = "./crates/nu_plugin_match", optional = true}
-nu_plugin_post = {version = "0.19.0", path = "./crates/nu_plugin_post", optional = true}
-nu_plugin_ps = {version = "0.19.0", path = "./crates/nu_plugin_ps", optional = true}
-nu_plugin_s3 = {version = "0.19.0", path = "./crates/nu_plugin_s3", optional = true}
-nu_plugin_start = {version = "0.19.0", path = "./crates/nu_plugin_start", optional = true}
-nu_plugin_sys = {version = "0.19.0", path = "./crates/nu_plugin_sys", optional = true}
-nu_plugin_textview = {version = "0.19.0", path = "./crates/nu_plugin_textview", optional = true}
-nu_plugin_to_bson = {version = "0.19.0", path = "./crates/nu_plugin_to_bson", optional = true}
-nu_plugin_to_sqlite = {version = "0.19.0", path = "./crates/nu_plugin_to_sqlite", optional = true}
-nu_plugin_tree = {version = "0.19.0", path = "./crates/nu_plugin_tree", optional = true}
+nu_plugin_binaryview = {version = "0.21.0", path = "./crates/nu_plugin_binaryview", optional = true}
+nu_plugin_chart = {version = "0.21.0", path = "./crates/nu_plugin_chart", optional = true}
+nu_plugin_fetch = {version = "0.21.0", path = "./crates/nu_plugin_fetch", optional = true}
+nu_plugin_from_bson = {version = "0.21.0", path = "./crates/nu_plugin_from_bson", optional = true}
+nu_plugin_from_sqlite = {version = "0.21.0", path = "./crates/nu_plugin_from_sqlite", optional = true}
+nu_plugin_inc = {version = "0.21.0", path = "./crates/nu_plugin_inc", optional = true}
+nu_plugin_match = {version = "0.21.0", path = "./crates/nu_plugin_match", optional = true}
+nu_plugin_post = {version = "0.21.0", path = "./crates/nu_plugin_post", optional = true}
+nu_plugin_ps = {version = "0.21.0", path = "./crates/nu_plugin_ps", optional = true}
+nu_plugin_s3 = {version = "0.21.0", path = "./crates/nu_plugin_s3", optional = true}
+nu_plugin_start = {version = "0.21.0", path = "./crates/nu_plugin_start", optional = true}
+nu_plugin_sys = {version = "0.21.0", path = "./crates/nu_plugin_sys", optional = true}
+nu_plugin_textview = {version = "0.21.0", path = "./crates/nu_plugin_textview", optional = true}
+nu_plugin_to_bson = {version = "0.21.0", path = "./crates/nu_plugin_to_bson", optional = true}
+nu_plugin_to_sqlite = {version = "0.21.0", path = "./crates/nu_plugin_to_sqlite", optional = true}
+nu_plugin_tree = {version = "0.21.0", path = "./crates/nu_plugin_tree", optional = true}
+nu_plugin_xpath = {version = "0.21.0", path = "./crates/nu_plugin_xpath", optional = true}
 
-crossterm = {version = "0.17.5", optional = true}
-semver = {version = "0.10.0", optional = true}
-url = {version = "2.1.1", optional = true}
-
-clap = "2.33.1"
-ctrlc = "3.1.4"
-dunce = "1.0.1"
-futures = {version = "0.3", features = ["compat", "io-compat"]}
-log = "0.4.8"
+# Required to bootstrap the main binary
+clap = "2.33.3"
+ctrlc = {version = "3.1.6", optional = true}
+futures = {version = "0.3.5", features = ["compat", "io-compat"]}
+log = "0.4.11"
 pretty_env_logger = "0.4.0"
-quick-xml = "0.18.1"
 
 [dev-dependencies]
-nu-test-support = {version = "0.19.0", path = "./crates/nu-test-support"}
+dunce = "1.0.1"
+nu-test-support = {version = "0.21.0", path = "./crates/nu-test-support"}
 
 [build-dependencies]
-serde = {version = "1.0.110", features = ["derive"]}
-toml = "0.5.6"
 
 [features]
+ctrlc-support = ["nu-cli/ctrlc"]
+directories-support = ["nu-cli/directories", "nu-cli/dirs", "nu-data/directories", "nu-data/dirs"]
+git-support = ["nu-cli/git2"]
+ptree-support = ["nu-cli/ptree"]
+rich-benchmark = ["nu-cli/rich-benchmark"]
+rustyline-support = ["nu-cli/rustyline-support"]
+term-support = ["nu-cli/term"]
+uuid-support = ["nu-cli/uuid_crate"]
+which-support = ["nu-cli/ichwh", "nu-cli/which"]
+
 default = [
   "sys",
   "ps",
@@ -75,40 +81,39 @@ default = [
   "ptree-support",
   "term-support",
   "uuid-support",
+  "rustyline-support",
   "match",
   "post",
   "fetch",
+  "rich-benchmark",
 ]
-extra = ["default", "binaryview", "tree", "clipboard-cli", "trash-support", "start", "bson", "sqlite", "s3"]
+extra = ["default", "binaryview", "tree", "clipboard-cli", "trash-support", "start", "bson", "sqlite", "s3", "chart", "xpath"]
 stable = ["default"]
 
-# Default
-inc = ["semver", "nu_plugin_inc"]
-ps = ["nu_plugin_ps"]
-sys = ["nu_plugin_sys"]
-textview = ["crossterm", "url", "nu_plugin_textview"]
+wasi = ["inc", "match", "directories-support", "ptree-support", "match", "tree", "rustyline-support"]
 
-# Stable
-binaryview = ["nu_plugin_binaryview"]
-bson = ["nu_plugin_from_bson", "nu_plugin_to_bson"]
+trace = ["nu-parser/trace"]
+
+# Stable (Default)
 fetch = ["nu_plugin_fetch"]
+inc = ["nu_plugin_inc"]
 match = ["nu_plugin_match"]
 post = ["nu_plugin_post"]
+ps = ["nu_plugin_ps"]
+sys = ["nu_plugin_sys"]
+textview = ["nu_plugin_textview"]
+
+# Extra
+binaryview = ["nu_plugin_binaryview"]
+bson = ["nu_plugin_from_bson", "nu_plugin_to_bson"]
+chart = ["nu_plugin_chart"]
+clipboard-cli = ["nu-cli/clipboard-cli"]
 s3 = ["nu_plugin_s3"]
 sqlite = ["nu_plugin_from_sqlite", "nu_plugin_to_sqlite"]
 start = ["nu_plugin_start"]
-trace = ["nu-parser/trace"]
-tree = ["nu_plugin_tree"]
-
-clipboard-cli = ["nu-cli/clipboard-cli"]
-ctrlc-support = ["nu-cli/ctrlc"]
-directories-support = ["nu-cli/directories", "nu-cli/dirs", "nu-data/directories", "nu-data/dirs"]
-git-support = ["nu-cli/git2"]
-ptree-support = ["nu-cli/ptree"]
-term-support = ["nu-cli/term"]
 trash-support = ["nu-cli/trash-support"]
-uuid-support = ["nu-cli/uuid_crate"]
-which-support = ["nu-cli/ichwh", "nu-cli/which"]
+tree = ["nu_plugin_tree"]
+xpath = ["nu_plugin_xpath"]
 
 # Core plugins that ship with `cargo install nu` by default
 # Currently, Cargo limits us to installing only one binary
@@ -170,6 +175,21 @@ name = "nu_plugin_extra_s3"
 path = "src/plugins/nu_plugin_extra_s3.rs"
 required-features = ["s3"]
 
+[[bin]]
+name = "nu_plugin_extra_chart_bar"
+path = "src/plugins/nu_plugin_extra_chart_bar.rs"
+required-features = ["chart"]
+
+[[bin]]
+name = "nu_plugin_extra_chart_line"
+path = "src/plugins/nu_plugin_extra_chart_line.rs"
+required-features = ["chart"]
+
+[[bin]]
+name = "nu_plugin_extra_xpath"
+path = "src/plugins/nu_plugin_extra_xpath.rs"
+required-features = ["xpath"]
+
 # Main nu binary
 [[bin]]
 name = "nu"

crates/nu-cli/Cargo.toml

@@ -4,103 +4,103 @@ description = "CLI for nushell"
 edition = "2018"
 license = "MIT"
 name = "nu-cli"
-version = "0.19.0"
+version = "0.21.0"
 
 [lib]
 doctest = false
 
 [dependencies]
-nu-data = {version = "0.19.0", path = "../nu-data"}
-nu-errors = {version = "0.19.0", path = "../nu-errors"}
-nu-parser = {version = "0.19.0", path = "../nu-parser"}
-nu-plugin = {version = "0.19.0", path = "../nu-plugin"}
-nu-protocol = {version = "0.19.0", path = "../nu-protocol"}
-nu-source = {version = "0.19.0", path = "../nu-source"}
-nu-table = {version = "0.19.0", path = "../nu-table"}
-nu-test-support = {version = "0.19.0", path = "../nu-test-support"}
-nu-value-ext = {version = "0.19.0", path = "../nu-value-ext"}
+nu-data = {version = "0.21.0", path = "../nu-data"}
+nu-errors = {version = "0.21.0", path = "../nu-errors"}
+nu-parser = {version = "0.21.0", path = "../nu-parser"}
+nu-plugin = {version = "0.21.0", path = "../nu-plugin"}
+nu-protocol = {version = "0.21.0", path = "../nu-protocol"}
+nu-source = {version = "0.21.0", path = "../nu-source"}
+nu-table = {version = "0.21.0", path = "../nu-table"}
+nu-test-support = {version = "0.21.0", path = "../nu-test-support"}
+nu-value-ext = {version = "0.21.0", path = "../nu-value-ext"}
 
 ansi_term = "0.12.1"
-app_dirs = {version = "2", package = "app_dirs2"}
 async-recursion = "0.3.1"
-async-trait = "0.1.36"
+async-trait = "0.1.40"
 base64 = "0.12.3"
-bigdecimal = {version = "0.1.2", features = ["serde"]}
-byte-unit = "3.1.3"
-bytes = "0.5.5"
-calamine = "0.16"
-chrono = {version = "0.4.11", features = ["serde"]}
-clap = "2.33.1"
+bigdecimal = {version = "0.2.0", features = ["serde"]}
+byte-unit = "4.0.9"
+bytes = "0.5.6"
+calamine = "0.16.1"
+chrono = {version = "0.4.15", features = ["serde"]}
+clap = "2.33.3"
 codespan-reporting = "0.9.5"
-csv = "1.1"
-ctrlc = {version = "3.1.4", optional = true}
+csv = "1.1.3"
+ctrlc = {version = "3.1.6", optional = true}
 derive-new = "0.5.8"
-directories = {version = "2.0.2", optional = true}
-dirs = {version = "2.0.2", optional = true}
-dtparse = "1.1.0"
+directories = {version = "3.0.1", optional = true}
+dirs = {version = "3.0.1", optional = true}
+dtparse = "1.2.0"
 dunce = "1.0.1"
 eml-parser = "0.1.0"
 filesize = "0.2.0"
-futures = {version = "0.3", features = ["compat", "io-compat"]}
+fs_extra = "1.2.0"
+futures = {version = "0.3.5", features = ["compat", "io-compat"]}
 futures-util = "0.3.5"
-futures_codec = "0.4"
+futures_codec = "0.4.1"
 getset = "0.1.1"
-git2 = {version = "0.13.6", default_features = false, optional = true}
+git2 = {version = "0.13.11", default_features = false, optional = true}
 glob = "0.3.0"
-hex = "0.4"
+heim = {version = "0.1.0-beta.3", optional = true}
 htmlescape = "0.3.1"
-ical = "0.6.*"
+ical = "0.6.0"
 ichwh = {version = "0.3.4", optional = true}
-indexmap = {version = "1.4.0", features = ["serde-1"]}
+indexmap = {version = "1.6.0", features = ["serde-1"]}
 itertools = "0.9.0"
-log = "0.4.8"
-meval = "0.2"
-natural = "0.5.0"
-num-bigint = {version = "0.2.6", features = ["serde"]}
-num-format = {version = "0.4", features = ["with-num-bigint"]}
-num-traits = "0.2.11"
+log = "0.4.11"
+meval = "0.2.0"
+num-bigint = {version = "0.3.0", features = ["serde"]}
+num-format = {version = "0.4.0", features = ["with-num-bigint"]}
+num-traits = "0.2.12"
 parking_lot = "0.11.0"
 pin-utils = "0.1.0"
-pretty-hex = "0.1.1"
-pretty_env_logger = "0.4.0"
-ptree = {version = "0.2", optional = true}
+pretty-hex = "0.2.0"
+ptree = {version = "0.3.0", optional = true}
 query_interface = "0.3.5"
-rand = "0.7"
-regex = "1"
+quick-xml = "0.18.1"
+rand = "0.7.3"
+regex = "1.3.9"
 roxmltree = "0.13.0"
 rust-embed = "5.6.0"
-rustyline = "6.2.0"
-serde = {version = "1.0.114", features = ["derive"]}
+rustyline = {version = "6.3.0", optional = true}
+serde = {version = "1.0.115", features = ["derive"]}
 serde-hjson = "0.9.1"
 serde_bytes = "0.11.5"
 serde_ini = "0.2.0"
-serde_json = "1.0.55"
-serde_urlencoded = "0.6.1"
-serde_yaml = "0.8"
+serde_json = "1.0.57"
+serde_urlencoded = "0.7.0"
+serde_yaml = "0.8.13"
 sha2 = "0.9.1"
 shellexpand = "2.0.0"
 strip-ansi-escapes = "0.1.0"
+sxd-document = "0.3.2"
+sxd-xpath = "0.4.2"
 tempfile = "3.1.0"
-term = {version = "0.5.2", optional = true}
+term = {version = "0.6.1", optional = true}
 term_size = "0.3.2"
 termcolor = "1.1.0"
 toml = "0.5.6"
-typetag = "0.1.5"
-umask = "1.0.0"
-unicode-xid = "0.2.1"
+unicode-segmentation = "1.6.0"
+uom = {version = "0.28.0", features = ["f64", "try-from"]}
 uuid_crate = {package = "uuid", version = "0.8.1", features = ["v4"], optional = true}
 which = {version = "4.0.2", optional = true}
-zip = {version = "0.5.6", optional = true}
+zip = {version = "0.5.7", optional = true}
 
-clipboard = {version = "0.5", optional = true}
-encoding_rs = "0.8.23"
-quick-xml = "0.18.1"
-rayon = "1.3.1"
-trash = {version = "1.0.1", optional = true}
-url = {version = "2.1.1"}
 Inflector = "0.11"
+clipboard = {version = "0.5.0", optional = true}
+encoding_rs = "0.8.24"
+rayon = "1.4.0"
+trash = {version = "1.1.1", optional = true}
+url = "2.1.1"
 
 [target.'cfg(unix)'.dependencies]
+umask = "1.0.0"
 users = "0.10.0"
 
 # TODO this will be possible with new dependency resolver
@@ -112,17 +112,18 @@ users = "0.10.0"
 [dependencies.rusqlite]
 features = ["bundled", "blob"]
 optional = true
-version = "0.23.1"
+version = "0.24.0"
 
 [build-dependencies]
-git2 = {version = "0.13", optional = true}
-
+git2 = {version = "0.13.11", optional = true}
 
 [dev-dependencies]
-quickcheck = "0.9"
-quickcheck_macros = "0.9"
+quickcheck = "0.9.2"
+quickcheck_macros = "0.9.1"
 
 [features]
 clipboard-cli = ["clipboard"]
+rich-benchmark = ["heim"]
+rustyline-support = ["rustyline"]
 stable = []
 trash-support = ["trash"]

crates/nu-cli/src/command_registry.rs

@@ -0,0 +1,64 @@
+use crate::commands::Command;
+use indexmap::IndexMap;
+use nu_errors::ShellError;
+use nu_parser::SignatureRegistry;
+use nu_protocol::Signature;
+use parking_lot::Mutex;
+use std::sync::Arc;
+
+#[derive(Debug, Clone, Default)]
+pub struct CommandRegistry {
+    registry: Arc<Mutex<IndexMap<String, Command>>>,
+}
+
+impl SignatureRegistry for CommandRegistry {
+    fn has(&self, name: &str) -> bool {
+        let registry = self.registry.lock();
+        registry.contains_key(name)
+    }
+    fn get(&self, name: &str) -> Option<Signature> {
+        let registry = self.registry.lock();
+        registry.get(name).map(|command| command.signature())
+    }
+    fn clone_box(&self) -> Box<dyn SignatureRegistry> {
+        Box::new(self.clone())
+    }
+}
+
+impl CommandRegistry {
+    pub fn new() -> CommandRegistry {
+        CommandRegistry {
+            registry: Arc::new(Mutex::new(IndexMap::default())),
+        }
+    }
+}
+
+impl CommandRegistry {
+    pub fn get_command(&self, name: &str) -> Option<Command> {
+        let registry = self.registry.lock();
+
+        registry.get(name).cloned()
+    }
+
+    pub fn expect_command(&self, name: &str) -> Result<Command, ShellError> {
+        self.get_command(name).ok_or_else(|| {
+            ShellError::untagged_runtime_error(format!("Could not load command: {}", name))
+        })
+    }
+
+    pub fn has(&self, name: &str) -> bool {
+        let registry = self.registry.lock();
+
+        registry.contains_key(name)
+    }
+
+    pub fn insert(&mut self, name: impl Into<String>, command: Command) {
+        let mut registry = self.registry.lock();
+        registry.insert(name.into(), command);
+    }
+
+    pub fn names(&self) -> Vec<String> {
+        let registry = self.registry.lock();
+        registry.keys().cloned().collect()
+    }
+}

crates/nu-cli/src/commands.rs

@@ -17,8 +17,9 @@ pub(crate) mod build_string;
 pub(crate) mod cal;
 pub(crate) mod cd;
 pub(crate) mod char_;
+pub(crate) mod chart;
 pub(crate) mod classified;
-#[cfg(feature = "clipboard")]
+#[cfg(feature = "clipboard-cli")]
 pub(crate) mod clip;
 pub(crate) mod command;
 pub(crate) mod compact;
@@ -29,13 +30,16 @@ pub(crate) mod cp;
 pub(crate) mod date;
 pub(crate) mod debug;
 pub(crate) mod default;
+pub(crate) mod describe;
 pub(crate) mod do_;
 pub(crate) mod drop;
 pub(crate) mod du;
 pub(crate) mod each;
 pub(crate) mod echo;
+pub(crate) mod empty;
 pub(crate) mod enter;
 pub(crate) mod every;
+pub(crate) mod exec;
 pub(crate) mod exit;
 pub(crate) mod first;
 pub(crate) mod format;
@@ -64,7 +68,6 @@ pub(crate) mod history;
 pub(crate) mod if_;
 pub(crate) mod insert;
 pub(crate) mod into_int;
-pub(crate) mod is_empty;
 pub(crate) mod keep;
 pub(crate) mod last;
 pub(crate) mod lines;
@@ -75,6 +78,7 @@ pub(crate) mod mkdir;
 pub(crate) mod move_;
 pub(crate) mod next;
 pub(crate) mod nth;
+pub(crate) mod nu;
 pub(crate) mod open;
 pub(crate) mod parse;
 pub(crate) mod path;
@@ -114,12 +118,10 @@ pub(crate) mod to_tsv;
 pub(crate) mod to_url;
 pub(crate) mod to_xml;
 pub(crate) mod to_yaml;
-pub(crate) mod trim;
 pub(crate) mod uniq;
 pub(crate) mod update;
 pub(crate) mod url_;
 pub(crate) mod version;
-pub(crate) mod what;
 pub(crate) mod where_;
 pub(crate) mod which_;
 pub(crate) mod with_env;
@@ -133,7 +135,7 @@ pub(crate) use command::{
 
 pub(crate) use alias::Alias;
 pub(crate) use ansi::Ansi;
-pub(crate) use append::Append;
+pub(crate) use append::Command as Append;
 pub(crate) use autoenv::Autoenv;
 pub(crate) use autoenv_trust::AutoenvTrust;
 pub(crate) use autoenv_untrust::AutoenvUnTrust;
@@ -141,6 +143,7 @@ pub(crate) use benchmark::Benchmark;
 pub(crate) use build_string::BuildString;
 pub(crate) use cal::Cal;
 pub(crate) use char_::Char;
+pub(crate) use chart::Chart;
 pub(crate) use compact::Compact;
 pub(crate) use config::{
     Config, ConfigClear, ConfigGet, ConfigLoad, ConfigPath, ConfigRemove, ConfigSet, ConfigSetInto,
@@ -150,14 +153,18 @@ pub(crate) use cp::Cpy;
 pub(crate) use date::{Date, DateFormat, DateNow, DateUTC};
 pub(crate) use debug::Debug;
 pub(crate) use default::Default;
+pub(crate) use describe::Describe;
 pub(crate) use do_::Do;
 pub(crate) use drop::Drop;
 pub(crate) use du::Du;
 pub(crate) use each::Each;
+pub(crate) use each::EachGroup;
+pub(crate) use each::EachWindow;
 pub(crate) use echo::Echo;
+pub(crate) use empty::Command as Empty;
 pub(crate) use if_::If;
-pub(crate) use is_empty::IsEmpty;
-pub(crate) use update::Update;
+pub(crate) use nu::NuPlugin;
+pub(crate) use update::Command as Update;
 pub(crate) mod kill;
 pub(crate) use kill::Kill;
 pub(crate) mod clear;
@@ -165,6 +172,7 @@ pub(crate) use clear::Clear;
 pub(crate) mod touch;
 pub(crate) use enter::Enter;
 pub(crate) use every::Every;
+pub(crate) use exec::Exec;
 pub(crate) use exit::Exit;
 pub(crate) use first::First;
 pub(crate) use format::Format;
@@ -185,13 +193,13 @@ pub(crate) use from_xml::FromXML;
 pub(crate) use from_yaml::FromYAML;
 pub(crate) use from_yaml::FromYML;
 pub(crate) use get::Get;
-pub(crate) use group_by::GroupBy;
+pub(crate) use group_by::Command as GroupBy;
 pub(crate) use group_by_date::GroupByDate;
 pub(crate) use headers::Headers;
 pub(crate) use help::Help;
 pub(crate) use histogram::Histogram;
 pub(crate) use history::History;
-pub(crate) use insert::Insert;
+pub(crate) use insert::Command as Insert;
 pub(crate) use into_int::IntoInt;
 pub(crate) use keep::{Keep, KeepUntil, KeepWhile};
 pub(crate) use last::Last;
@@ -218,7 +226,7 @@ pub(crate) use prev::Previous;
 pub(crate) use pwd::Pwd;
 #[cfg(feature = "uuid_crate")]
 pub(crate) use random::RandomUUID;
-pub(crate) use random::{Random, RandomBool, RandomDice};
+pub(crate) use random::{Random, RandomBool, RandomDice, RandomInteger};
 pub(crate) use range::Range;
 pub(crate) use reduce::Reduce;
 pub(crate) use reject::Reject;
@@ -238,9 +246,9 @@ pub(crate) use split::{Split, SplitChars, SplitColumn, SplitRow};
 pub(crate) use split_by::SplitBy;
 pub(crate) use str_::{
     Str, StrCamelCase, StrCapitalize, StrCollect, StrContains, StrDowncase, StrEndsWith,
-    StrFindReplace, StrFrom, StrIndexOf, StrKebabCase, StrLength, StrPascalCase, StrReverse,
-    StrScreamingSnakeCase, StrSet, StrSnakeCase, StrStartsWith, StrSubstring, StrToDatetime,
-    StrToDecimal, StrToInteger, StrTrim, StrTrimLeft, StrTrimRight, StrUpcase,
+    StrFindReplace, StrFrom, StrIndexOf, StrKebabCase, StrLPad, StrLength, StrPascalCase, StrRPad,
+    StrReverse, StrScreamingSnakeCase, StrSet, StrSnakeCase, StrStartsWith, StrSubstring,
+    StrToDatetime, StrToDecimal, StrToInteger, StrTrim, StrTrimLeft, StrTrimRight, StrUpcase,
 };
 pub(crate) use table::Table;
 pub(crate) use tags::Tags;
@@ -255,12 +263,46 @@ pub(crate) use to_url::ToURL;
 pub(crate) use to_xml::ToXML;
 pub(crate) use to_yaml::ToYAML;
 pub(crate) use touch::Touch;
-pub(crate) use trim::Trim;
 pub(crate) use uniq::Uniq;
 pub(crate) use url_::{UrlCommand, UrlHost, UrlPath, UrlQuery, UrlScheme};
 pub(crate) use version::Version;
-pub(crate) use what::What;
 pub(crate) use where_::Where;
 pub(crate) use which_::Which;
 pub(crate) use with_env::WithEnv;
 pub(crate) use wrap::Wrap;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::commands::whole_stream_command;
+    use crate::examples::{test_anchors, test_examples};
+    use nu_errors::ShellError;
+
+    fn commands() -> Vec<Command> {
+        vec![
+            whole_stream_command(Append),
+            whole_stream_command(GroupBy),
+            whole_stream_command(Insert),
+            whole_stream_command(Update),
+            whole_stream_command(Empty),
+        ]
+    }
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        for cmd in commands() {
+            test_examples(cmd)?;
+        }
+
+        Ok(())
+    }
+
+    #[test]
+    fn tracks_metadata() -> Result<(), ShellError> {
+        for cmd in commands() {
+            test_anchors(cmd)?;
+        }
+
+        Ok(())
+    }
+}

crates/nu-cli/src/commands/alias.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_data::config;
 use nu_errors::ShellError;
@@ -340,11 +340,12 @@ fn find_block_shapes(block: &Block, registry: &CommandRegistry) -> Result<ShapeM
 #[cfg(test)]
 mod tests {
     use super::Alias;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Alias {})
+        Ok(test_examples(Alias {})?)
     }
 }

crates/nu-cli/src/commands/ansi.rs

@@ -135,11 +135,12 @@ pub fn str_to_ansi_color(s: String) -> Option<String> {
 #[cfg(test)]
 mod tests {
     use super::Ansi;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Ansi {})
+        Ok(test_examples(Ansi {})?)
     }
 }

crates/nu-cli/src/commands/append.rs

@@ -1,18 +1,18 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 
 #[derive(Deserialize)]
-struct AppendArgs {
+struct Arguments {
     row: Value,
 }
 
-pub struct Append;
+pub struct Command;
 
 #[async_trait]
-impl WholeStreamCommand for Append {
+impl WholeStreamCommand for Command {
     fn name(&self) -> &str {
         "append"
     }
@@ -34,11 +34,18 @@ impl WholeStreamCommand for Append {
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        let (AppendArgs { row }, input) = args.process(registry).await?;
+        let (Arguments { mut row }, input) = args.process(registry).await?;
 
-        let eos = futures::stream::iter(vec![row]);
+        let input: Vec<Value> = input.collect().await;
 
-        Ok(input.chain(eos).to_output_stream())
+        if let Some(first) = input.get(0) {
+            row.tag = first.tag();
+        }
+
+        Ok(
+            futures::stream::iter(input.into_iter().chain(vec![row]).map(ReturnSuccess::value))
+                .to_output_stream(),
+        )
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -54,15 +61,3 @@ impl WholeStreamCommand for Append {
         }]
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::Append;
-
-    #[test]
-    fn examples_work_as_expected() {
-        use crate::examples::test as test_examples;
-
-        test_examples(Append {})
-    }
-}

crates/nu-cli/src/commands/autoview/command.rs

@@ -318,7 +318,7 @@ fn create_default_command_args(context: &RunnableContextWithoutInput) -> RawComm
                 external_redirection: ExternalRedirection::Stdout,
             },
             name_tag: context.name.clone(),
-            scope: Scope::new(),
+            scope: Scope::create(),
         },
     }
 }
@@ -326,11 +326,12 @@ fn create_default_command_args(context: &RunnableContextWithoutInput) -> RawComm
 #[cfg(test)]
 mod tests {
     use super::Command;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Command {})
+        Ok(test_examples(Command {})?)
     }
 }

crates/nu-cli/src/commands/autoview/options.rs

@@ -10,25 +10,16 @@ pub enum AutoPivotMode {
 
 impl AutoPivotMode {
     pub fn is_auto(&self) -> bool {
-        match &self {
-            AutoPivotMode::Auto => true,
-            _ => false,
-        }
+        matches!(self, AutoPivotMode::Auto)
     }
 
     pub fn is_always(&self) -> bool {
-        match &self {
-            AutoPivotMode::Always => true,
-            _ => false,
-        }
+        matches!(self, AutoPivotMode::Always)
     }
 
     #[allow(unused)]
     pub fn is_never(&self) -> bool {
-        match &self {
-            AutoPivotMode::Never => true,
-            _ => false,
-        }
+        matches!(self, AutoPivotMode::Never)
     }
 }
 
@@ -37,7 +28,7 @@ pub trait ConfigExtensions: Debug + Send {
 }
 
 pub fn pivot_mode(config: &NuConfig) -> AutoPivotMode {
-    let vars = config.vars.lock();
+    let vars = &config.vars;
 
     if let Some(mode) = vars.get("pivot_mode") {
         let mode = match mode.as_string() {

crates/nu-cli/src/commands/benchmark.rs

@@ -1,18 +1,26 @@
 use crate::commands::classified::block::run_block;
 use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
+#[cfg(feature = "rich-benchmark")]
+use heim::cpu::time;
 use nu_errors::ShellError;
 use nu_protocol::{
-    hir::Block, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
+    hir::{Block, ClassifiedCommand, Commands, InternalCommand},
+    Dictionary, Scope, Signature, SyntaxShape, UntaggedValue, Value,
 };
-
-use chrono::prelude::*;
+use rand::{
+    distributions::Alphanumeric,
+    prelude::{thread_rng, Rng},
+};
+use std::convert::TryInto;
+use std::time::{Duration, Instant};
 
 pub struct Benchmark;
 
 #[derive(Deserialize, Debug)]
 struct BenchmarkArgs {
     block: Block,
+    passthrough: Option<Block>,
 }
 
 #[async_trait]
@@ -22,15 +30,22 @@ impl WholeStreamCommand for Benchmark {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("benchmark").required(
-            "block",
-            SyntaxShape::Block,
-            "the block to run and benchmark",
-        )
+        Signature::build("benchmark")
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run and benchmark",
+            )
+            .named(
+                "passthrough",
+                SyntaxShape::Block,
+                "Display the benchmark results and pass through the block's output",
+                Some('p'),
+            )
     }
 
     fn usage(&self) -> &str {
-        "Runs a block and return the time it took to do execute it. Eg) benchmark { echo $nu.env.NAME }"
+        "Runs a block and returns the time it took to execute it"
     }
 
     async fn run(
@@ -40,6 +55,21 @@ impl WholeStreamCommand for Benchmark {
     ) -> Result<OutputStream, ShellError> {
         benchmark(args, registry).await
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Benchmarks a command within a block",
+                example: "benchmark { sleep 500ms }",
+                result: None,
+            },
+            Example {
+                description: "Benchmarks a command within a block and passes its output through",
+                example: "echo 45 | benchmark { sleep 500ms } --passthrough {}",
+                result: Some(vec![UntaggedValue::int(45).into()]),
+            },
+        ]
+    }
 }
 
 async fn benchmark(
@@ -48,31 +78,135 @@ async fn benchmark(
 ) -> Result<OutputStream, ShellError> {
     let registry = registry.clone();
 
-    let mut context = Context::from_raw(&raw_args, &registry);
+    let tag = raw_args.call_info.args.span;
+    let mut context = EvaluationContext::from_raw(&raw_args, &registry);
     let scope = raw_args.call_info.scope.clone();
-    let (BenchmarkArgs { block }, input) = raw_args.process(&registry).await?;
+    let (BenchmarkArgs { block, passthrough }, input) = raw_args.process(&registry).await?;
 
-    let start_time: chrono::DateTime<_> = Utc::now();
+    let env = scope.env();
+    let name = generate_free_name(&env);
+    let mut env = IndexMap::new();
+    env.insert(name, generate_random_env_value());
+    let scope = Scope::append_env(scope, env);
 
-    let result = run_block(
-        &block,
-        &mut context,
-        input,
-        &scope.it,
-        &scope.vars,
-        &scope.env,
-    )
-    .await;
+    let start_time = Instant::now();
 
-    let _ = result?.drain_vec().await;
-    let run_duration: chrono::Duration = Utc::now().signed_duration_since(start_time);
+    #[cfg(feature = "rich-benchmark")]
+    let start = time().await;
 
+    let result = run_block(&block, &mut context, input, scope.clone()).await;
+    let output = result?.into_vec().await;
+
+    #[cfg(feature = "rich-benchmark")]
+    let end = time().await;
+
+    let end_time = Instant::now();
     context.clear_errors();
 
-    let output = Ok(ReturnSuccess::Value(Value {
-        value: UntaggedValue::Primitive(Primitive::from(run_duration)),
-        tag: Tag::from(block.span),
-    }));
+    // return basic runtime
+    #[cfg(not(feature = "rich-benchmark"))]
+    {
+        let mut indexmap = IndexMap::with_capacity(1);
 
-    Ok(OutputStream::from(vec![output]))
+        let real_time = into_big_int(end_time - start_time);
+        indexmap.insert("real time".to_string(), real_time);
+        benchmark_output(indexmap, output, passthrough, &tag, &mut context, scope).await
+    }
+    // return advanced stats
+    #[cfg(feature = "rich-benchmark")]
+    if let (Ok(start), Ok(end)) = (start, end) {
+        let mut indexmap = IndexMap::with_capacity(4);
+
+        let real_time = into_big_int(end_time - start_time);
+        indexmap.insert("real time".to_string(), real_time);
+
+        let user_time = into_big_int(end.user() - start.user());
+        indexmap.insert("user time".to_string(), user_time);
+
+        let system_time = into_big_int(end.system() - start.system());
+        indexmap.insert("system time".to_string(), system_time);
+
+        let idle_time = into_big_int(end.idle() - start.idle());
+        indexmap.insert("idle time".to_string(), idle_time);
+
+        benchmark_output(indexmap, output, passthrough, &tag, &mut context, scope).await
+    } else {
+        Err(ShellError::untagged_runtime_error(
+            "Could not retreive CPU time",
+        ))
+    }
+}
+
+async fn benchmark_output<T, Output>(
+    indexmap: IndexMap<String, BigInt>,
+    block_output: Output,
+    passthrough: Option<Block>,
+    tag: T,
+    context: &mut EvaluationContext,
+    scope: Arc<Scope>,
+) -> Result<OutputStream, ShellError>
+where
+    T: Into<Tag> + Copy,
+    Output: Into<OutputStream>,
+{
+    let value = UntaggedValue::Row(Dictionary::from(
+        indexmap
+            .into_iter()
+            .map(|(k, v)| (k, UntaggedValue::duration(v).into_value(tag)))
+            .collect::<IndexMap<String, Value>>(),
+    ))
+    .into_value(tag);
+
+    if let Some(time_block) = passthrough {
+        let benchmark_output = InputStream::one(value);
+
+        // add autoview for an empty block
+        let time_block = add_implicit_autoview(time_block);
+
+        let _ = run_block(&time_block, context, benchmark_output, scope).await?;
+        context.clear_errors();
+
+        Ok(block_output.into())
+    } else {
+        let benchmark_output = OutputStream::one(value);
+        Ok(benchmark_output)
+    }
+}
+
+fn add_implicit_autoview(mut block: Block) -> Block {
+    if block.block.is_empty() {
+        block.push({
+            let mut commands = Commands::new(block.span);
+            commands.push(ClassifiedCommand::Internal(InternalCommand::new(
+                "autoview".to_string(),
+                block.span,
+                block.span,
+            )));
+            commands
+        });
+    }
+    block
+}
+
+fn into_big_int<T: TryInto<Duration>>(time: T) -> BigInt {
+    time.try_into()
+        .unwrap_or_else(|_| Duration::new(0, 0))
+        .as_nanos()
+        .into()
+}
+
+fn generate_random_env_value() -> String {
+    let mut thread_rng = thread_rng();
+    let len = thread_rng.gen_range(1, 16 * 1024);
+    thread_rng.sample_iter(&Alphanumeric).take(len).collect()
+}
+
+fn generate_free_name(env: &indexmap::IndexMap<String, String>) -> String {
+    let mut thread_rng = thread_rng();
+    loop {
+        let candidate_name = format!("NU_RANDOM_VALUE_{}", thread_rng.gen::<usize>());
+        if !env.contains_key(&candidate_name) {
+            return candidate_name;
+        }
+    }
 }

crates/nu-cli/src/commands/cal.rs

@@ -339,11 +339,12 @@ fn add_month_to_table(
 #[cfg(test)]
 mod tests {
     use super::Cal;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Cal {})
+        Ok(test_examples(Cal {})?)
     }
 }

crates/nu-cli/src/commands/cd.rs

@@ -72,11 +72,12 @@ impl WholeStreamCommand for Cd {
 #[cfg(test)]
 mod tests {
     use super::Cd;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Cd {})
+        Ok(test_examples(Cd {})?)
     }
 }

crates/nu-cli/src/commands/char_.rs

@@ -94,6 +94,35 @@ fn str_to_character(s: &str) -> Option<String> {
         "high_voltage_sign" | "elevated" => Some('\u{26a1}'.to_string()),           // ⚡
         "tilde" | "twiddle" | "squiggly" | "home" => Some("~".into()),              // ~
         "hash" | "hashtag" | "pound_sign" | "sharp" | "root" => Some("#".into()),   // #
+
+        // Weather symbols
+        "sun" => Some("\x1b[33;1m\u{2600}\x1b[0m".to_string()), // Yellow Bold ☀
+        "moon" => Some("\x1b[36m\u{263d}\x1b[0m".to_string()),  // Cyan ☽
+        "clouds" => Some("\x1b[37;1m\u{2601}\x1b[0m".to_string()), // White Bold ☁
+        "rain" => Some("\x1b[37;1m\u{2614}\x1b[0m".to_string()), // White Bold ☔
+        "fog" => Some("\x1b[37;1m\u{2592}\x1b[0m".to_string()), // White Bold ▒
+        "mist" => Some("\x1b[34m\u{2591}\x1b[0m".to_string()),  // Blue ░
+        "haze" => Some("\x1b[33m\u{2591}\x1b[0m".to_string()),  // Yellow ░
+        "snow" => Some("\x1b[37;1m\u{2744}\x1b[0m".to_string()), // White Bold ❄
+        "thunderstorm" => Some("\x1b[33;1m\u{26a1}\x1b[0m".to_string()), // Yellow Bold ⚡
+
+        // Reference for ansi codes https://gist.github.com/fnky/458719343aabd01cfb17a3a4f7296797
+        // Another good reference http://ascii-table.com/ansi-escape-sequences.php
+
+        // For setting title like `echo [$(char title) $(pwd) $(char bel)] | str collect`
+        "title" => Some("\x1b]2;".to_string()), // ESC]2; xterm sets window title
+        "bel" => Some('\x07'.to_string()),      // Terminal Bell
+        "backspace" => Some('\x08'.to_string()), // Backspace
+
+        // Ansi Erase Sequences
+        "clear_screen" => Some("\x1b[J".to_string()), // clears the screen
+        "clear_screen_from_cursor_to_end" => Some("\x1b[0J".to_string()), // clears from cursor until end of screen
+        "clear_screen_from_cursor_to_beginning" => Some("\x1b[1J".to_string()), // clears from cursor to beginning of screen
+        "cls" | "clear_entire_screen" => Some("\x1b[2J".to_string()), // clears the entire screen
+        "erase_line" => Some("\x1b[K".to_string()),                   // clears the current line
+        "erase_line_from_cursor_to_end" => Some("\x1b[0K".to_string()), // clears from cursor to end of line
+        "erase_line_from_cursor_to_beginning" => Some("\x1b[1K".to_string()), // clears from cursor to start of line
+        "erase_entire_line" => Some("\x1b[2K".to_string()),                   // clears entire line
         _ => None,
     }
 }
@@ -101,11 +130,12 @@ fn str_to_character(s: &str) -> Option<String> {
 #[cfg(test)]
 mod tests {
     use super::Char;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Char {})
+        Ok(test_examples(Char {})?)
     }
 }

crates/nu-cli/src/commands/chart.rs

@@ -0,0 +1,53 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+#[derive(Clone)]
+pub struct Chart;
+
+#[async_trait]
+impl WholeStreamCommand for Chart {
+    fn name(&self) -> &str {
+        "chart"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("chart")
+    }
+
+    fn usage(&self) -> &str {
+        "Displays charts."
+    }
+
+    async fn run(
+        &self,
+        _args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        if registry.get_command("chart bar").is_none() {
+            return Err(ShellError::untagged_runtime_error(
+                "nu_plugin_chart not installed.",
+            ));
+        }
+
+        let registry = registry.clone();
+        Ok(OutputStream::one(Ok(ReturnSuccess::Value(
+            UntaggedValue::string(crate::commands::help::get_help(&Chart, &registry))
+                .into_value(Tag::unknown()),
+        ))))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Chart;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Chart {})?)
+    }
+}

crates/nu-cli/src/commands/classified/block.rs

@@ -1,21 +1,19 @@
 use crate::commands::classified::expr::run_expression_block;
 use crate::commands::classified::internal::run_internal_command;
-use crate::context::Context;
+use crate::evaluation_context::EvaluationContext;
 use crate::prelude::*;
 use crate::stream::InputStream;
 use futures::stream::TryStreamExt;
 use nu_errors::ShellError;
 use nu_protocol::hir::{Block, ClassifiedCommand, Commands};
-use nu_protocol::{ReturnSuccess, UntaggedValue, Value};
+use nu_protocol::{ReturnSuccess, Scope, UntaggedValue, Value};
 use std::sync::atomic::Ordering;
 
 pub(crate) async fn run_block(
     block: &Block,
-    ctx: &mut Context,
+    ctx: &mut EvaluationContext,
     mut input: InputStream,
-    it: &Value,
-    vars: &IndexMap<String, Value>,
-    env: &IndexMap<String, String>,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     let mut output: Result<InputStream, ShellError> = Ok(InputStream::empty());
     for pipeline in &block.block {
@@ -54,7 +52,7 @@ pub(crate) async fn run_block(
                 return Err(e);
             }
         }
-        output = run_pipeline(pipeline, ctx, input, it, vars, env).await;
+        output = run_pipeline(pipeline, ctx, input, scope.clone()).await;
 
         input = InputStream::empty();
     }
@@ -64,11 +62,9 @@ pub(crate) async fn run_block(
 
 async fn run_pipeline(
     commands: &Commands,
-    ctx: &mut Context,
+    ctx: &mut EvaluationContext,
     mut input: InputStream,
-    it: &Value,
-    vars: &IndexMap<String, Value>,
-    env: &IndexMap<String, String>,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     for item in commands.list.clone() {
         input = match item {
@@ -77,13 +73,13 @@ async fn run_pipeline(
             }
 
             ClassifiedCommand::Expr(expr) => {
-                run_expression_block(*expr, ctx, it, vars, env).await?
+                run_expression_block(*expr, ctx, scope.clone()).await?
             }
 
             ClassifiedCommand::Error(err) => return Err(err.into()),
 
             ClassifiedCommand::Internal(left) => {
-                run_internal_command(left, ctx, input, it, vars, env).await?
+                run_internal_command(left, ctx, input, scope.clone()).await?
             }
         };
     }

crates/nu-cli/src/commands/classified/expr.rs

@@ -6,14 +6,12 @@ use log::{log_enabled, trace};
 use futures::stream::once;
 use nu_errors::ShellError;
 use nu_protocol::hir::SpannedExpression;
-use nu_protocol::Value;
+use nu_protocol::Scope;
 
 pub(crate) async fn run_expression_block(
     expr: SpannedExpression,
-    context: &mut Context,
-    it: &Value,
-    vars: &IndexMap<String, Value>,
-    env: &IndexMap<String, String>,
+    context: &mut EvaluationContext,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     if log_enabled!(log::Level::Trace) {
         trace!(target: "nu::run::expr", "->");
@@ -21,7 +19,7 @@ pub(crate) async fn run_expression_block(
     }
 
     let registry = context.registry().clone();
-    let output = evaluate_baseline_expr(&expr, &registry, it, vars, env).await?;
+    let output = evaluate_baseline_expr(&expr, &registry, scope).await?;
 
     Ok(once(async { Ok(output) }).to_input_stream())
 }

crates/nu-cli/src/commands/classified/external.rs

@@ -19,9 +19,9 @@ use nu_source::Tag;
 
 pub(crate) async fn run_external_command(
     command: ExternalCommand,
-    context: &mut Context,
+    context: &mut EvaluationContext,
     input: InputStream,
-    scope: &Scope,
+    scope: Arc<Scope>,
     external_redirection: ExternalRedirection,
 ) -> Result<InputStream, ShellError> {
     trace!(target: "nu::run::external", "-> {}", command.name);
@@ -39,9 +39,9 @@ pub(crate) async fn run_external_command(
 
 async fn run_with_stdin(
     command: ExternalCommand,
-    context: &mut Context,
+    context: &mut EvaluationContext,
     input: InputStream,
-    scope: &Scope,
+    scope: Arc<Scope>,
     external_redirection: ExternalRedirection,
 ) -> Result<InputStream, ShellError> {
     let path = context.shell_manager.path();
@@ -50,9 +50,7 @@ async fn run_with_stdin(
 
     let mut command_args = vec![];
     for arg in command.args.iter() {
-        let value =
-            evaluate_baseline_expr(arg, &context.registry, &scope.it, &scope.vars, &scope.env)
-                .await?;
+        let value = evaluate_baseline_expr(arg, &context.registry, scope.clone()).await?;
 
         // Skip any arguments that don't really exist, treating them as optional
         // FIXME: we may want to preserve the gap in the future, though it's hard to say
@@ -138,7 +136,7 @@ fn spawn(
     args: &[String],
     input: InputStream,
     external_redirection: ExternalRedirection,
-    scope: &Scope,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     let command = command.clone();
 
@@ -169,7 +167,7 @@ fn spawn(
     trace!(target: "nu::run::external", "cwd = {:?}", &path);
 
     process.env_clear();
-    process.envs(scope.env.iter());
+    process.envs(scope.env());
 
     // We want stdout regardless of what
     // we are doing ($it case or pipe stdin)
@@ -543,7 +541,7 @@ mod tests {
         add_quotes, argument_contains_whitespace, argument_is_quoted, expand_tilde, remove_quotes,
     };
     #[cfg(feature = "which")]
-    use super::{run_external_command, Context, InputStream};
+    use super::{run_external_command, EvaluationContext, InputStream};
 
     #[cfg(feature = "which")]
     use futures::executor::block_on;
@@ -573,13 +571,14 @@ mod tests {
         let cmd = ExternalBuilder::for_name("i_dont_exist.exe").build();
 
         let input = InputStream::empty();
-        let mut ctx = Context::basic().expect("There was a problem creating a basic context.");
+        let mut ctx =
+            EvaluationContext::basic().expect("There was a problem creating a basic context.");
 
         assert!(run_external_command(
             cmd,
             &mut ctx,
             input,
-            &Scope::new(),
+            Scope::create(),
             ExternalRedirection::Stdout
         )
         .await
@@ -591,7 +590,7 @@ mod tests {
     // async fn failure_run() -> Result<(), ShellError> {
     //     let cmd = ExternalBuilder::for_name("fail").build();
 
-    //     let mut ctx = Context::basic().expect("There was a problem creating a basic context.");
+    //     let mut ctx = EvaluationContext::basic().expect("There was a problem creating a basic context.");
     //     let stream = run_external_command(cmd, &mut ctx, None, false)
     //         .await?
     //         .expect("There was a problem running the external command.");

crates/nu-cli/src/commands/classified/internal.rs

@@ -9,22 +9,15 @@ use nu_protocol::{CommandAction, Primitive, ReturnSuccess, Scope, UntaggedValue,
 
 pub(crate) async fn run_internal_command(
     command: InternalCommand,
-    context: &mut Context,
+    context: &mut EvaluationContext,
     input: InputStream,
-    it: &Value,
-    vars: &IndexMap<String, Value>,
-    env: &IndexMap<String, String>,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     if log_enabled!(log::Level::Trace) {
         trace!(target: "nu::run::internal", "->");
         trace!(target: "nu::run::internal", "{}", command.name);
     }
 
-    let scope = Scope {
-        it: it.clone(),
-        vars: vars.clone(),
-        env: env.clone(),
-    };
     let objects: InputStream = trace_stream!(target: "nu::trace_stream::internal", "input" = input);
     let internal_command = context.expect_command(&command.name);
 
@@ -38,7 +31,7 @@ pub(crate) async fn run_internal_command(
                 internal_command?,
                 Tag::unknown_anchor(command.name_span),
                 command.args.clone(),
-                &scope,
+                scope.clone(),
                 objects,
             )
             .await?
@@ -48,8 +41,6 @@ pub(crate) async fn run_internal_command(
     //let context = Arc::new(context.clone());
     let context = context.clone();
     let command = Arc::new(command);
-    let scope = Arc::new(scope);
-    // let scope = scope.clone();
 
     Ok(InputStream::from_stream(
         result
@@ -90,7 +81,7 @@ pub(crate) async fn run_internal_command(
                                                 external_redirection: ExternalRedirection::Stdout,
                                             },
                                             name_tag: Tag::unknown_anchor(command.name_span),
-                                            scope: (&*scope).clone(),
+                                            scope,
                                         },
                                     };
                                     let result = converter
@@ -200,6 +191,28 @@ pub(crate) async fn run_internal_command(
                                 )]);
                                 InputStream::from_stream(futures::stream::iter(vec![]))
                             }
+                            CommandAction::AddPlugins(path) => {
+                                match crate::plugin::scan(vec![std::path::PathBuf::from(path)]) {
+                                    Ok(plugins) => {
+                                        context.add_commands(
+                                            plugins
+                                                .into_iter()
+                                                .filter(|p| {
+                                                    !context.is_command_registered(p.name())
+                                                })
+                                                .collect(),
+                                        );
+
+                                        InputStream::from_stream(futures::stream::iter(vec![]))
+                                    }
+                                    Err(reason) => {
+                                        context.error(reason.clone());
+                                        InputStream::one(
+                                            UntaggedValue::Error(reason).into_untagged_value(),
+                                        )
+                                    }
+                                }
+                            }
                             CommandAction::PreviousShell => {
                                 context.shell_manager.prev();
                                 InputStream::from_stream(futures::stream::iter(vec![]))

crates/nu-cli/src/commands/classified/plugin.rs

@@ -130,7 +130,7 @@ async fn run_filter(
         UntaggedValue::Primitive(Primitive::EndOfStream).into_untagged_value()
     ]);
 
-    let args = args.evaluate_once_with_scope(&registry, &scope).await?;
+    let args = args.evaluate_once_with_scope(&registry, scope).await?;
 
     let real_path = Path::new(&path);
     let ext = real_path.extension();

crates/nu-cli/src/commands/clear.rs

@@ -17,7 +17,7 @@ impl WholeStreamCommand for Clear {
     }
 
     fn usage(&self) -> &str {
-        "clears the terminal"
+        "Clears the terminal"
     }
 
     async fn run(&self, _: CommandArgs, _: &CommandRegistry) -> Result<OutputStream, ShellError> {
@@ -43,15 +43,3 @@ impl WholeStreamCommand for Clear {
         }]
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::Clear;
-
-    #[test]
-    fn examples_work_as_expected() {
-        use crate::examples::test as test_examples;
-
-        test_examples(Clear {})
-    }
-}

crates/nu-cli/src/commands/clip.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use futures::stream::StreamExt;
 use nu_errors::ShellError;
@@ -32,11 +32,18 @@ impl WholeStreamCommand for Clip {
     }
 
     fn examples(&self) -> Vec<Example> {
-        vec![Example {
-            description: "Save text to the clipboard",
-            example: "echo 'secret value' | clip",
-            result: None,
-        }]
+        vec![
+            Example {
+                description: "Save text to the clipboard",
+                example: "echo 'secret value' | clip",
+                result: None,
+            },
+            Example {
+                description: "Save numbers to the clipboard",
+                example: "random integer 10000000..99999999 | clip",
+                result: None,
+            },
+        ]
     }
 }
 
@@ -61,16 +68,14 @@ pub async fn clip(
                     first = false;
                 }
 
-                let string: String = match i.as_string() {
-                    Ok(string) => string.to_string(),
-                    Err(_) => {
-                        return Err(ShellError::labeled_error(
-                            "Given non-string data",
-                            "expected strings from pipeline",
-                            name,
-                        ))
-                    }
-                };
+                let string: String = i.convert_to_string();
+                if string.is_empty() {
+                    return Err(ShellError::labeled_error(
+                        "Unable to convert to string",
+                        "Unable to convert to string",
+                        name,
+                    ));
+                }
 
                 new_copy_data.push_str(&string);
             }
@@ -99,11 +104,12 @@ pub async fn clip(
 #[cfg(test)]
 mod tests {
     use super::Clip;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Clip {})
+        Ok(test_examples(Clip {})?)
     }
 }

crates/nu-cli/src/commands/command.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::help::get_help;
-use crate::context::CommandRegistry;
 use crate::deserializer::ConfigDeserializer;
 use crate::evaluate::evaluate_args::evaluate_args;
 use crate::prelude::*;
@@ -17,27 +17,12 @@ use std::sync::atomic::AtomicBool;
 pub struct UnevaluatedCallInfo {
     pub args: hir::Call,
     pub name_tag: Tag,
-    pub scope: Scope,
+    pub scope: Arc<Scope>,
 }
 
 impl UnevaluatedCallInfo {
     pub async fn evaluate(self, registry: &CommandRegistry) -> Result<CallInfo, ShellError> {
-        let args = evaluate_args(&self.args, registry, &self.scope).await?;
-
-        Ok(CallInfo {
-            args,
-            name_tag: self.name_tag,
-        })
-    }
-
-    pub async fn evaluate_with_new_it(
-        self,
-        registry: &CommandRegistry,
-        it: &Value,
-    ) -> Result<CallInfo, ShellError> {
-        let mut scope = self.scope.clone();
-        scope.it = it.clone();
-        let args = evaluate_args(&self.args, registry, &scope).await?;
+        let args = evaluate_args(&self.args, registry, self.scope.clone()).await?;
 
         Ok(CallInfo {
             args,
@@ -115,7 +100,7 @@ impl CommandArgs {
     pub async fn evaluate_once_with_scope(
         self,
         registry: &CommandRegistry,
-        scope: &Scope,
+        scope: Arc<Scope>,
     ) -> Result<EvaluatedWholeStreamCommandArgs, ShellError> {
         let host = self.host.clone();
         let ctrl_c = self.ctrl_c.clone();
@@ -215,37 +200,6 @@ impl EvaluatedWholeStreamCommandArgs {
     }
 }
 
-#[derive(Getters)]
-#[get = "pub"]
-pub struct EvaluatedFilterCommandArgs {
-    args: EvaluatedCommandArgs,
-}
-
-impl Deref for EvaluatedFilterCommandArgs {
-    type Target = EvaluatedCommandArgs;
-    fn deref(&self) -> &Self::Target {
-        &self.args
-    }
-}
-
-impl EvaluatedFilterCommandArgs {
-    pub fn new(
-        host: Arc<parking_lot::Mutex<dyn Host>>,
-        ctrl_c: Arc<AtomicBool>,
-        shell_manager: ShellManager,
-        call_info: CallInfo,
-    ) -> EvaluatedFilterCommandArgs {
-        EvaluatedFilterCommandArgs {
-            args: EvaluatedCommandArgs {
-                host,
-                ctrl_c,
-                shell_manager,
-                call_info,
-            },
-        }
-    }
-}
-
 #[derive(Getters, new)]
 #[get = "pub(crate)"]
 pub struct EvaluatedCommandArgs {
@@ -303,6 +257,11 @@ pub trait WholeStreamCommand: Send + Sync {
         false
     }
 
+    // Commands that are not meant to be run by users
+    fn is_internal(&self) -> bool {
+        false
+    }
+
     fn examples(&self) -> Vec<Example> {
         Vec::new()
     }
@@ -367,74 +326,15 @@ impl Command {
         self.0.is_binary()
     }
 
+    pub fn is_internal(&self) -> bool {
+        self.0.is_internal()
+    }
+
     pub fn stream_command(&self) -> &dyn WholeStreamCommand {
         &*self.0
     }
 }
 
-pub struct FnFilterCommand {
-    name: String,
-    func: fn(EvaluatedFilterCommandArgs) -> Result<OutputStream, ShellError>,
-}
-
-#[async_trait]
-impl WholeStreamCommand for FnFilterCommand {
-    fn name(&self) -> &str {
-        &self.name
-    }
-
-    fn usage(&self) -> &str {
-        "usage"
-    }
-
-    async fn run(
-        &self,
-        CommandArgs {
-            host,
-            ctrl_c,
-            shell_manager,
-            call_info,
-            input,
-            ..
-        }: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        let registry = Arc::new(registry.clone());
-        let func = self.func;
-
-        Ok(input
-            .then(move |it| {
-                let host = host.clone();
-                let registry = registry.clone();
-                let ctrl_c = ctrl_c.clone();
-                let shell_manager = shell_manager.clone();
-                let call_info = call_info.clone();
-                async move {
-                    let call_info = match call_info.evaluate_with_new_it(&*registry, &it).await {
-                        Err(err) => {
-                            return OutputStream::one(Err(err));
-                        }
-                        Ok(args) => args,
-                    };
-
-                    let args = EvaluatedFilterCommandArgs::new(
-                        host.clone(),
-                        ctrl_c.clone(),
-                        shell_manager.clone(),
-                        call_info,
-                    );
-
-                    match func(args) {
-                        Err(err) => return OutputStream::one(Err(err)),
-                        Ok(stream) => stream,
-                    }
-                }
-            })
-            .flatten()
-            .to_output_stream())
-    }
-}
-
 pub fn whole_stream_command(command: impl WholeStreamCommand + 'static) -> Command {
     Command(Arc::new(command))
 }

crates/nu-cli/src/commands/compact.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use futures::future;
 use futures::stream::StreamExt;
@@ -37,22 +37,11 @@ impl WholeStreamCommand for Compact {
     }
 
     fn examples(&self) -> Vec<Example> {
-        vec![
-            Example {
-                description: "Filter out all null entries in a list",
-                example: "echo [1 2 $null 3 $null $null] | compact",
-                result: Some(vec![
-                    UntaggedValue::int(1).into(),
-                    UntaggedValue::int(2).into(),
-                    UntaggedValue::int(3).into(),
-                ]),
-            },
-            Example {
-                description: "Filter out all directory entries having no 'target'",
-                example: "ls -la | compact target",
-                result: None,
-            },
-        ]
+        vec![Example {
+            description: "Filter out all directory entries having no 'target'",
+            example: "ls -la | compact target",
+            result: None,
+        }]
     }
 }
 
@@ -95,11 +84,12 @@ pub async fn compact(
 #[cfg(test)]
 mod tests {
     use super::Compact;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Compact {})
+        Ok(test_examples(Compact {})?)
     }
 }

crates/nu-cli/src/commands/config/clear.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};

crates/nu-cli/src/commands/config/get.rs

@@ -1,15 +1,14 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
-use nu_source::Tagged;
+use nu_protocol::{ColumnPath, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 
 pub struct SubCommand;
 
 #[derive(Deserialize)]
 pub struct GetArgs {
-    get: Tagged<String>,
+    path: ColumnPath,
 }
 
 #[async_trait]
@@ -21,7 +20,7 @@ impl WholeStreamCommand for SubCommand {
     fn signature(&self) -> Signature {
         Signature::build("config get").required(
             "get",
-            SyntaxShape::Any,
+            SyntaxShape::ColumnPath,
             "value to get from the config",
         )
     }
@@ -51,17 +50,14 @@ pub async fn get(
     args: CommandArgs,
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
-    let name_span = args.call_info.name_tag.clone();
-    let (GetArgs { get }, _) = args.process(&registry).await?;
+    let name_tag = args.call_info.name_tag.clone();
+    let (GetArgs { path }, _) = args.process(&registry).await?;
 
     // NOTE: None because we are not loading a new config file, we just want to read from the
     // existing config
-    let result = nu_data::config::read(name_span, &None)?;
+    let result = UntaggedValue::row(nu_data::config::read(&name_tag, &None)?).into_value(&name_tag);
 
-    let key = get.to_string();
-    let value = result
-        .get(&key)
-        .ok_or_else(|| ShellError::labeled_error("Missing key in config", "key", get.tag()))?;
+    let value = crate::commands::get::get_column_path(&path, &result)?;
 
     Ok(match value {
         Value {
@@ -75,9 +71,6 @@ pub async fn get(
 
             futures::stream::iter(list).to_output_stream()
         }
-        x => {
-            let x = x.clone();
-            OutputStream::one(ReturnSuccess::value(x))
-        }
+        x => OutputStream::one(ReturnSuccess::value(x)),
     })
 }

crates/nu-cli/src/commands/config/load.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};

crates/nu-cli/src/commands/config/path.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Primitive, ReturnSuccess, Signature, UntaggedValue};

crates/nu-cli/src/commands/config/remove.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};

crates/nu-cli/src/commands/config/set.rs

@@ -1,15 +1,14 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
-use nu_source::Tagged;
+use nu_protocol::{ColumnPath, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 
 pub struct SubCommand;
 
 #[derive(Deserialize)]
 pub struct SetArgs {
-    key: Tagged<String>,
+    path: ColumnPath,
     value: Value,
 }
 
@@ -21,7 +20,7 @@ impl WholeStreamCommand for SubCommand {
 
     fn signature(&self) -> Signature {
         Signature::build("config set")
-            .required("key", SyntaxShape::String, "variable name to set")
+            .required("key", SyntaxShape::ColumnPath, "variable name to set")
             .required("value", SyntaxShape::Any, "value to use")
     }
 
@@ -38,11 +37,28 @@ impl WholeStreamCommand for SubCommand {
     }
 
     fn examples(&self) -> Vec<Example> {
-        vec![Example {
-            description: "Set nonzero_exit_errors to true",
-            example: "config set nonzero_exit_errors $true",
-            result: None,
-        }]
+        vec![
+            Example {
+                description: "Set auto pivoting",
+                example: "config set pivot_mode always",
+                result: None,
+            },
+            Example {
+                description: "Set line editor options",
+                example: "config set line_editor [[edit_mode, completion_type]; [emacs circular]]",
+                result: None,
+            },
+            Example {
+                description: "Set coloring options",
+                example: "config set color_config [[header_align header_bold]; [left $true]]",
+                result: None,
+            },
+            Example {
+                description: "Set nested options",
+                example: "config set color_config.header_color white",
+                result: None,
+            },
+        ]
     }
 }
 
@@ -50,18 +66,32 @@ pub async fn set(
     args: CommandArgs,
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
-    let name_span = args.call_info.name_tag.clone();
-    let (SetArgs { key, value }, _) = args.process(&registry).await?;
+    let name_tag = args.call_info.name_tag.clone();
+    let (SetArgs { path, mut value }, _) = args.process(&registry).await?;
 
     // NOTE: None because we are not loading a new config file, we just want to read from the
     // existing config
-    let mut result = nu_data::config::read(name_span, &None)?;
+    let raw_entries = nu_data::config::read(&name_tag, &None)?;
+    let configuration = UntaggedValue::row(raw_entries).into_value(&name_tag);
 
-    result.insert(key.to_string(), value.clone());
+    if let UntaggedValue::Table(rows) = &value.value {
+        if rows.len() == 1 && rows[0].is_row() {
+            value = rows[0].clone();
+        }
+    }
 
-    config::write(&result, &None)?;
+    match configuration.forgiving_insert_data_at_column_path(&path, value) {
+        Ok(Value {
+            value: UntaggedValue::Row(changes),
+            ..
+        }) => {
+            config::write(&changes.entries, &None)?;
 
-    Ok(OutputStream::one(ReturnSuccess::value(
-        UntaggedValue::Row(result.into()).into_value(&value.tag),
-    )))
+            Ok(OutputStream::one(ReturnSuccess::value(
+                UntaggedValue::Row(changes).into_value(name_tag),
+            )))
+        }
+        Ok(_) => Ok(OutputStream::empty()),
+        Err(reason) => Err(reason),
+    }
 }

crates/nu-cli/src/commands/config/set_into.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};

crates/nu-cli/src/commands/count.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use futures::stream::StreamExt;
 use nu_errors::ShellError;
@@ -80,11 +80,12 @@ impl WholeStreamCommand for Count {
 #[cfg(test)]
 mod tests {
     use super::Count;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Count {})
+        Ok(test_examples(Count {})?)
     }
 }

crates/nu-cli/src/commands/cp.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape};
@@ -66,11 +66,12 @@ impl WholeStreamCommand for Cpy {
 #[cfg(test)]
 mod tests {
     use super::Cpy;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Cpy {})
+        Ok(test_examples(Cpy {})?)
     }
 }

crates/nu-cli/src/commands/date/command.rs

@@ -16,7 +16,7 @@ impl WholeStreamCommand for Command {
     }
 
     fn usage(&self) -> &str {
-        "Work with dates."
+        "Apply date function"
     }
 
     async fn run(
@@ -36,11 +36,12 @@ impl WholeStreamCommand for Command {
 #[cfg(test)]
 mod tests {
     use super::Command;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Command {})
+        Ok(test_examples(Command {})?)
     }
 }

crates/nu-cli/src/commands/date/format.rs

@@ -61,3 +61,16 @@ pub async fn format(
 
     Ok(OutputStream::one(value))
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/date/now.rs

@@ -48,3 +48,16 @@ pub async fn now(
 
     Ok(OutputStream::one(value))
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/date/utc.rs

@@ -48,3 +48,16 @@ pub async fn utc(
 
     Ok(OutputStream::one(value))
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/debug.rs

@@ -55,11 +55,12 @@ async fn debug_value(
 #[cfg(test)]
 mod tests {
     use super::Debug;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Debug {})
+        Ok(test_examples(Debug {})?)
     }
 }

crates/nu-cli/src/commands/default.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
@@ -83,11 +83,12 @@ async fn default(
 #[cfg(test)]
 mod tests {
     use super::Default;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Default {})
+        Ok(test_examples(Default {})?)
     }
 }

crates/nu-cli/src/commands/describe.rs

@@ -4,13 +4,13 @@ use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
 
-pub struct What;
+pub struct Describe;
 
 #[derive(Deserialize)]
-pub struct WhatArgs {}
+pub struct DescribeArgs {}
 
 #[async_trait]
-impl WholeStreamCommand for What {
+impl WholeStreamCommand for Describe {
     fn name(&self) -> &str {
         "describe"
     }
@@ -28,11 +28,11 @@ impl WholeStreamCommand for What {
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        what(args, registry).await
+        describe(args, registry).await
     }
 }
 
-pub async fn what(
+pub async fn describe(
     args: CommandArgs,
     _registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
@@ -49,12 +49,13 @@ pub async fn what(
 
 #[cfg(test)]
 mod tests {
-    use super::What;
+    use super::Describe;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(What {})
+        Ok(test_examples(Describe {})?)
     }
 }

crates/nu-cli/src/commands/do_.rs

@@ -65,7 +65,7 @@ async fn do_(
     let registry = registry.clone();
     let external_redirection = raw_args.call_info.args.external_redirection;
 
-    let mut context = Context::from_raw(&raw_args, &registry);
+    let mut context = EvaluationContext::from_raw(&raw_args, &registry);
     let scope = raw_args.call_info.scope.clone();
     let (
         DoArgs {
@@ -95,15 +95,7 @@ async fn do_(
 
     block.set_redirect(block_redirection);
 
-    let result = run_block(
-        &block,
-        &mut context,
-        input,
-        &scope.it,
-        &scope.vars,
-        &scope.env,
-    )
-    .await;
+    let result = run_block(&block, &mut context, input, scope).await;
 
     if ignore_errors {
         // To properly ignore errors we need to redirect stderr, consume it, and remove
@@ -125,11 +117,12 @@ async fn do_(
 #[cfg(test)]
 mod tests {
     use super::Do;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Do {})
+        Ok(test_examples(Do {})?)
     }
 }

crates/nu-cli/src/commands/drop.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
@@ -85,11 +85,12 @@ async fn drop(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStr
 #[cfg(test)]
 mod tests {
     use super::Drop;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Drop {})
+        Ok(test_examples(Drop {})?)
     }
 }

crates/nu-cli/src/commands/du.rs

@@ -427,11 +427,12 @@ impl From<FileInfo> for Value {
 #[cfg(test)]
 mod tests {
     use super::Du;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Du {})
+        Ok(test_examples(Du {})?)
     }
 }

crates/nu-cli/src/commands/each/command.rs

@@ -1,6 +1,6 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::classified::block::run_block;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 
 use futures::stream::once;
@@ -84,7 +84,7 @@ pub async fn process_row(
     block: Arc<Block>,
     scope: Arc<Scope>,
     head: Arc<Box<SpannedExpression>>,
-    mut context: Arc<Context>,
+    mut context: Arc<EvaluationContext>,
     input: Value,
 ) -> Result<OutputStream, ShellError> {
     let input_clone = input.clone();
@@ -97,9 +97,7 @@ pub async fn process_row(
         &block,
         Arc::make_mut(&mut context),
         input_stream,
-        &input,
-        &scope.vars,
-        &scope.env,
+        Scope::append_it(scope, input),
     )
     .await?
     .to_output_stream())
@@ -119,8 +117,8 @@ async fn each(
 ) -> Result<OutputStream, ShellError> {
     let registry = registry.clone();
     let head = Arc::new(raw_args.call_info.args.head.clone());
-    let scope = Arc::new(raw_args.call_info.scope.clone());
-    let context = Arc::new(Context::from_raw(&raw_args, &registry));
+    let scope = raw_args.call_info.scope.clone();
+    let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
     let (each_args, input): (EachArgs, _) = raw_args.process(&registry).await?;
     let block = Arc::new(each_args.block);
 
@@ -166,11 +164,12 @@ async fn each(
 #[cfg(test)]
 mod tests {
     use super::Each;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Each {})
+        Ok(test_examples(Each {})?)
     }
 }

crates/nu-cli/src/commands/each/group.rs

@@ -0,0 +1,134 @@
+use crate::commands::each::process_row;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{
+    hir::Block, hir::SpannedExpression, ReturnSuccess, Scope, Signature, SyntaxShape,
+    UntaggedValue, Value,
+};
+use nu_source::Tagged;
+use serde::Deserialize;
+
+pub struct EachGroup;
+
+#[derive(Deserialize)]
+pub struct EachGroupArgs {
+    group_size: Tagged<usize>,
+    block: Block,
+    //numbered: Tagged<bool>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for EachGroup {
+    fn name(&self) -> &str {
+        "each group"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("each group")
+            .required("group_size", SyntaxShape::Int, "the size of each group")
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run on each group",
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Runs a block on groups of `group_size` rows of a table at a time."
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Echo the sum of each pair",
+            example: "echo [1 2 3 4] | each group 2 { echo $it | math sum }",
+            result: None,
+        }]
+    }
+
+    async fn run(
+        &self,
+        raw_args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let registry = registry.clone();
+        let head = Arc::new(raw_args.call_info.args.head.clone());
+        let scope = raw_args.call_info.scope.clone();
+        let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
+        let (each_args, input): (EachGroupArgs, _) = raw_args.process(&registry).await?;
+        let block = Arc::new(each_args.block);
+
+        Ok(input
+            .chunks(each_args.group_size.item)
+            .then(move |input| {
+                run_block_on_vec(
+                    input,
+                    block.clone(),
+                    scope.clone(),
+                    head.clone(),
+                    context.clone(),
+                )
+            })
+            .flatten()
+            .to_output_stream())
+    }
+}
+
+pub(crate) fn run_block_on_vec(
+    input: Vec<Value>,
+    block: Arc<Block>,
+    scope: Arc<Scope>,
+    head: Arc<Box<SpannedExpression>>,
+    context: Arc<EvaluationContext>,
+) -> impl Future<Output = OutputStream> {
+    let value = Value {
+        value: UntaggedValue::Table(input),
+        tag: Tag::unknown(),
+    };
+
+    async {
+        match process_row(block, scope, head, context, value).await {
+            Ok(s) => {
+                // We need to handle this differently depending on whether process_row
+                // returned just 1 value or if it returned multiple as a stream.
+                let vec = s.collect::<Vec<_>>().await;
+
+                // If it returned just one value, just take that value
+                if vec.len() == 1 {
+                    return OutputStream::one(vec.into_iter().next().expect(
+                        "This should be impossible, we just checked that vec.len() == 1.",
+                    ));
+                }
+
+                // If it returned multiple values, we need to put them into a table and
+                // return that.
+                let result = vec.into_iter().collect::<Result<Vec<ReturnSuccess>, _>>();
+                let result_table = match result {
+                    Ok(t) => t,
+                    Err(e) => return OutputStream::one(Err(e)),
+                };
+
+                let table = result_table
+                    .into_iter()
+                    .filter_map(|x| x.raw_value())
+                    .collect();
+
+                OutputStream::one(Ok(ReturnSuccess::Value(UntaggedValue::Table(table).into())))
+            }
+            Err(e) => OutputStream::one(Err(e)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::EachGroup;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(EachGroup {})?)
+    }
+}

crates/nu-cli/src/commands/each/mod.rs

@@ -0,0 +1,9 @@
+pub mod command;
+pub mod group;
+pub mod window;
+
+pub(crate) use command::make_indexed_item;
+pub use command::process_row;
+pub use command::Each;
+pub use group::EachGroup;
+pub use window::EachWindow;

crates/nu-cli/src/commands/each/window.rs

@@ -0,0 +1,114 @@
+use crate::commands::each::group::run_block_on_vec;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+//use itertools::Itertools;
+use nu_errors::ShellError;
+use nu_protocol::{hir::Block, Primitive, Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+use serde::Deserialize;
+
+pub struct EachWindow;
+
+#[derive(Deserialize)]
+pub struct EachWindowArgs {
+    window_size: Tagged<usize>,
+    block: Block,
+    stride: Option<Tagged<usize>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for EachWindow {
+    fn name(&self) -> &str {
+        "each window"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("each window")
+            .required("window_size", SyntaxShape::Int, "the size of each window")
+            .named(
+                "stride",
+                SyntaxShape::Int,
+                "the number of rows to slide over between windows",
+                Some('s'),
+            )
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run on each group",
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Runs a block on sliding windows of `window_size` rows of a table at a time."
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Echo the sum of each window",
+            example: "echo [1 2 3 4] | each window 2 { echo $it | math sum }",
+            result: None,
+        }]
+    }
+
+    async fn run(
+        &self,
+        raw_args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let registry = registry.clone();
+        let head = Arc::new(raw_args.call_info.args.head.clone());
+        let scope = raw_args.call_info.scope.clone();
+        let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
+        let (each_args, mut input): (EachWindowArgs, _) = raw_args.process(&registry).await?;
+        let block = Arc::new(each_args.block);
+
+        let mut window: Vec<_> = input
+            .by_ref()
+            .take(*each_args.window_size - 1)
+            .collect::<Vec<_>>()
+            .await;
+
+        // `window` must start with dummy values, which will be removed on the first iteration
+        let stride = each_args.stride.map(|x| *x).unwrap_or(1);
+        window.insert(0, UntaggedValue::Primitive(Primitive::Nothing).into());
+
+        Ok(input
+            .enumerate()
+            .then(move |(i, input)| {
+                // This would probably be more efficient if `last` was a VecDeque
+                // But we can't have that because it needs to be put into a Table
+                window.remove(0);
+                window.push(input);
+
+                let block = block.clone();
+                let scope = scope.clone();
+                let head = head.clone();
+                let context = context.clone();
+                let local_window = window.clone();
+
+                async move {
+                    if i % stride == 0 {
+                        Some(run_block_on_vec(local_window, block, scope, head, context).await)
+                    } else {
+                        None
+                    }
+                }
+            })
+            .filter_map(|x| async { x })
+            .flatten()
+            .to_output_stream())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::EachWindow;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(EachWindow {})?)
+    }
+}

crates/nu-cli/src/commands/echo.rs

@@ -81,17 +81,20 @@ struct RangeIterator {
     end: Primitive,
     tag: Tag,
     is_end_inclusive: bool,
-    is_done: bool,
 }
 
 impl RangeIterator {
     pub fn new(range: Range, tag: Tag) -> RangeIterator {
+        let start = match range.from.0.item {
+            Primitive::Nothing => Primitive::Int(0.into()),
+            x => x,
+        };
+
         RangeIterator {
-            curr: range.from.0.item,
+            curr: start,
             end: range.to.0.item,
             tag,
             is_end_inclusive: matches!(range.to.1, RangeInclusion::Inclusive),
-            is_done: false,
         }
     }
 }
@@ -99,14 +102,40 @@ impl RangeIterator {
 impl Iterator for RangeIterator {
     type Item = Result<ReturnSuccess, ShellError>;
     fn next(&mut self) -> Option<Self::Item> {
-        if self.curr != self.end {
+        let ordering = if self.end == Primitive::Nothing {
+            Ordering::Less
+        } else {
+            let result =
+                nu_data::base::coerce_compare_primitive(&self.curr, &self.end).map_err(|_| {
+                    ShellError::labeled_error(
+                        "Cannot create range",
+                        "unsupported range",
+                        self.tag.span,
+                    )
+                });
+
+            if let Err(result) = result {
+                return Some(Err(result));
+            }
+
+            let result = result
+                .expect("Internal error: the error case was already protected, but that failed");
+
+            result.compare()
+        };
+
+        use std::cmp::Ordering;
+
+        if (ordering == Ordering::Less) || (self.is_end_inclusive && ordering == Ordering::Equal) {
             let output = UntaggedValue::Primitive(self.curr.clone()).into_value(self.tag.clone());
 
-            self.curr = match nu_data::value::compute_values(
+            let next_value = nu_data::value::compute_values(
                 Operator::Plus,
                 &UntaggedValue::Primitive(self.curr.clone()),
                 &UntaggedValue::int(1),
-            ) {
+            );
+
+            self.curr = match next_value {
                 Ok(result) => match result {
                     UntaggedValue::Primitive(p) => p,
                     _ => {
@@ -123,11 +152,6 @@ impl Iterator for RangeIterator {
                 }
             };
             Some(ReturnSuccess::value(output))
-        } else if self.is_end_inclusive && !self.is_done {
-            self.is_done = true;
-            Some(ReturnSuccess::value(
-                UntaggedValue::Primitive(self.curr.clone()).into_value(self.tag.clone()),
-            ))
         } else {
             // TODO: add inclusive/exclusive ranges
             None
@@ -138,11 +162,12 @@ impl Iterator for RangeIterator {
 #[cfg(test)]
 mod tests {
     use super::Echo;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Echo {})
+        Ok(test_examples(Echo {})?)
     }
 }

crates/nu-cli/src/commands/empty.rs

@@ -0,0 +1,288 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::classified::block::run_block;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{
+    hir::Block, ColumnPath, Primitive, ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue,
+    Value,
+};
+use nu_source::Tagged;
+use nu_value_ext::{as_string, ValueExt};
+
+use futures::stream::once;
+use indexmap::indexmap;
+
+#[derive(Deserialize)]
+pub struct Arguments {
+    rest: Vec<Value>,
+}
+
+pub struct Command;
+
+#[async_trait]
+impl WholeStreamCommand for Command {
+    fn name(&self) -> &str {
+        "empty?"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("empty?").rest(
+            SyntaxShape::Any,
+            "the names of the columns to check emptiness. Pass an optional block to replace if empty",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Check for empty values"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        is_empty(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Check if a value is empty",
+                example: "echo '' | empty?",
+                result: Some(vec![UntaggedValue::boolean(true).into()]),
+            },
+            Example {
+                description: "more than one column",
+                example: "echo [[meal size]; [arepa small] [taco '']] | empty? meal size",
+                result: Some(
+                    vec![
+                        UntaggedValue::row(indexmap! {
+                                "meal".to_string() => Value::from(false),
+                                "size".to_string() => Value::from(false),
+                        })
+                        .into(),
+                        UntaggedValue::row(indexmap! {
+                                "meal".to_string() => Value::from(false),
+                                "size".to_string() => Value::from(true),
+                        })
+                        .into(),
+                    ],
+                ),
+            },Example {
+                description: "use a block if setting the empty cell contents is wanted",
+                example: "echo [[2020/04/16 2020/07/10 2020/11/16]; ['' [27] [37]]] | empty? 2020/04/16 { = [33 37] }",
+                result: Some(
+                    vec![
+                        UntaggedValue::row(indexmap! {
+                                "2020/04/16".to_string() => UntaggedValue::table(&[UntaggedValue::int(33).into(), UntaggedValue::int(37).into()]).into(),
+                                "2020/07/10".to_string() => UntaggedValue::table(&[UntaggedValue::int(27).into()]).into(),
+                                "2020/11/16".to_string() => UntaggedValue::table(&[UntaggedValue::int(37).into()]).into(),
+                        })
+                        .into(),
+                    ],
+                ),
+            },
+        ]
+    }
+}
+
+async fn is_empty(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let tag = args.call_info.name_tag.clone();
+    let name_tag = Arc::new(args.call_info.name_tag.clone());
+    let context = Arc::new(EvaluationContext::from_raw(&args, &registry));
+    let scope = args.call_info.scope.clone();
+    let (Arguments { rest }, input) = args.process(&registry).await?;
+    let (columns, default_block): (Vec<ColumnPath>, Option<Block>) = arguments(rest)?;
+    let default_block = Arc::new(default_block);
+
+    if input.is_empty() {
+        let stream = futures::stream::iter(vec![
+            UntaggedValue::Primitive(Primitive::Nothing).into_value(tag)
+        ]);
+
+        return Ok(InputStream::from_stream(stream)
+            .then(move |input| {
+                let tag = name_tag.clone();
+                let scope = scope.clone();
+                let context = context.clone();
+                let block = default_block.clone();
+                let columns = vec![];
+
+                async {
+                    match process_row(scope, context, input, block, columns, tag).await {
+                        Ok(s) => s,
+                        Err(e) => OutputStream::one(Err(e)),
+                    }
+                }
+            })
+            .flatten()
+            .to_output_stream());
+    }
+
+    Ok(input
+        .then(move |input| {
+            let tag = name_tag.clone();
+            let scope = scope.clone();
+            let context = context.clone();
+            let block = default_block.clone();
+            let columns = columns.clone();
+
+            async {
+                match process_row(scope, context, input, block, columns, tag).await {
+                    Ok(s) => s,
+                    Err(e) => OutputStream::one(Err(e)),
+                }
+            }
+        })
+        .flatten()
+        .to_output_stream())
+}
+
+fn arguments(rest: Vec<Value>) -> Result<(Vec<ColumnPath>, Option<Block>), ShellError> {
+    let mut rest = rest;
+    let mut columns = vec![];
+    let mut default = None;
+
+    let last_argument = rest.pop();
+
+    match last_argument {
+        Some(Value {
+            value: UntaggedValue::Block(call),
+            ..
+        }) => default = Some(call),
+        Some(other) => {
+            let Tagged { item: path, .. } = other.as_column_path()?;
+
+            columns = vec![path];
+        }
+        None => {}
+    };
+
+    for argument in rest {
+        let Tagged { item: path, .. } = argument.as_column_path()?;
+
+        columns.push(path);
+    }
+
+    Ok((columns, default))
+}
+
+async fn process_row(
+    scope: Arc<Scope>,
+    mut context: Arc<EvaluationContext>,
+    input: Value,
+    default_block: Arc<Option<Block>>,
+    column_paths: Vec<ColumnPath>,
+    tag: Arc<Tag>,
+) -> Result<OutputStream, ShellError> {
+    let _tag = &*tag;
+    let mut out = Arc::new(None);
+    let results = Arc::make_mut(&mut out);
+
+    if let Some(default_block) = &*default_block {
+        let for_block = input.clone();
+        let input_stream = once(async { Ok(for_block) }).to_input_stream();
+
+        let scope = Scope::append_it(scope, input.clone());
+
+        let mut stream = run_block(
+            &default_block,
+            Arc::make_mut(&mut context),
+            input_stream,
+            scope,
+        )
+        .await?;
+
+        *results = Some({
+            let values = stream.drain_vec().await;
+
+            let errors = context.get_errors();
+
+            if let Some(error) = errors.first() {
+                return Err(error.clone());
+            }
+
+            if values.len() == 1 {
+                let value = values
+                    .get(0)
+                    .ok_or_else(|| ShellError::unexpected("No value."))?;
+
+                Value {
+                    value: value.value.clone(),
+                    tag: input.tag.clone(),
+                }
+            } else if values.is_empty() {
+                UntaggedValue::nothing().into_value(&input.tag)
+            } else {
+                UntaggedValue::table(&values).into_value(&input.tag)
+            }
+        });
+    }
+
+    match input {
+        Value {
+            value: UntaggedValue::Row(ref r),
+            ref tag,
+        } => {
+            if column_paths.is_empty() {
+                Ok(OutputStream::one(ReturnSuccess::value({
+                    let is_empty = input.is_empty();
+
+                    if default_block.is_some() {
+                        if is_empty {
+                            results
+                                .clone()
+                                .unwrap_or_else(|| UntaggedValue::boolean(true).into_value(tag))
+                        } else {
+                            input.clone()
+                        }
+                    } else {
+                        UntaggedValue::boolean(is_empty).into_value(tag)
+                    }
+                })))
+            } else {
+                let mut obj = input.clone();
+
+                for column in column_paths.clone() {
+                    let path = UntaggedValue::Primitive(Primitive::ColumnPath(column.clone()))
+                        .into_value(tag);
+                    let data = r.get_data(&as_string(&path)?).borrow().clone();
+                    let is_empty = data.is_empty();
+
+                    let default = if default_block.is_some() {
+                        if is_empty {
+                            results
+                                .clone()
+                                .unwrap_or_else(|| UntaggedValue::boolean(true).into_value(tag))
+                        } else {
+                            data.clone()
+                        }
+                    } else {
+                        UntaggedValue::boolean(is_empty).into_value(tag)
+                    };
+
+                    if let Ok(value) =
+                        obj.swap_data_by_column_path(&column, Box::new(move |_| Ok(default)))
+                    {
+                        obj = value;
+                    }
+                }
+
+                Ok(OutputStream::one(ReturnSuccess::value(obj)))
+            }
+        }
+        other => Ok(OutputStream::one(ReturnSuccess::value({
+            if other.is_empty() {
+                results
+                    .clone()
+                    .unwrap_or_else(|| UntaggedValue::boolean(true).into_value(other.tag))
+            } else {
+                UntaggedValue::boolean(false).into_value(other.tag)
+            }
+        }))),
+    }
+}

crates/nu-cli/src/commands/enter.rs

@@ -1,6 +1,6 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::UnevaluatedCallInfo;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::hir::ExternalRedirection;
@@ -191,11 +191,12 @@ async fn enter(
 #[cfg(test)]
 mod tests {
     use super::Enter;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Enter {})
+        Ok(test_examples(Enter {})?)
     }
 }

crates/nu-cli/src/commands/every.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};
@@ -93,11 +93,12 @@ async fn every(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputSt
 #[cfg(test)]
 mod tests {
     use super::Every;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Every {})
+        Ok(test_examples(Every {})?)
     }
 }

crates/nu-cli/src/commands/exec.rs

@@ -0,0 +1,87 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{Signature, SyntaxShape};
+use nu_source::Tagged;
+use std::path::PathBuf;
+
+pub struct Exec;
+
+#[derive(Deserialize)]
+pub struct ExecArgs {
+    pub command: Tagged<PathBuf>,
+    pub rest: Vec<Tagged<String>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Exec {
+    fn name(&self) -> &str {
+        "exec"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("exec")
+            .required("command", SyntaxShape::Path, "the command to execute")
+            .rest(SyntaxShape::Pattern, "any additional arguments for command")
+    }
+
+    fn usage(&self) -> &str {
+        "Execute command"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        exec(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Execute 'ps aux'",
+                example: "exec ps aux",
+                result: None,
+            },
+            Example {
+                description: "Execute 'nautilus'",
+                example: "exec nautilus",
+                result: None,
+            },
+        ]
+    }
+}
+
+#[cfg(unix)]
+async fn exec(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    use std::os::unix::process::CommandExt;
+    use std::process::Command;
+
+    let registry = registry.clone();
+    let name = args.call_info.name_tag.clone();
+    let (args, _): (ExecArgs, _) = args.process(&registry).await?;
+
+    let mut command = Command::new(args.command.item);
+    for tagged_arg in args.rest {
+        command.arg(tagged_arg.item);
+    }
+
+    let err = command.exec(); // this replaces our process, should not return
+
+    Err(ShellError::labeled_error(
+        "Error on exec",
+        format!("{}", err),
+        &name,
+    ))
+}
+
+#[cfg(not(unix))]
+async fn exec(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    Err(ShellError::labeled_error(
+        "Error on exec",
+        "exec is not supported on your platform",
+        &args.call_info.name_tag,
+    ))
+}

crates/nu-cli/src/commands/exit.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::command::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{CommandAction, ReturnSuccess, Signature};
@@ -63,11 +63,12 @@ pub async fn exit(
 #[cfg(test)]
 mod tests {
     use super::Exit;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Exit {})
+        Ok(test_examples(Exit {})?)
     }
 }

crates/nu-cli/src/commands/first.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
@@ -72,11 +72,12 @@ async fn first(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputSt
 #[cfg(test)]
 mod tests {
     use super::First;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(First {})
+        Ok(test_examples(First {})?)
     }
 }

crates/nu-cli/src/commands/format.rs

@@ -1,9 +1,9 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::evaluate::evaluate_baseline_expr;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};
+use nu_protocol::{ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue};
 use nu_source::Tagged;
 use std::borrow::Borrow;
 
@@ -54,7 +54,7 @@ async fn format_command(
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
     let registry = Arc::new(registry.clone());
-    let scope = Arc::new(args.call_info.scope.clone());
+    let scope = args.call_info.scope.clone();
     let (FormatArgs { pattern }, input) = args.process(&registry).await?;
 
     let format_pattern = format(&pattern);
@@ -83,9 +83,7 @@ async fn format_command(
                             let result = evaluate_baseline_expr(
                                 &full_column_path.0,
                                 &registry,
-                                &value,
-                                &scope.vars,
-                                &scope.env,
+                                Scope::append_it(scope.clone(), value.clone()),
                             )
                             .await;
 
@@ -153,11 +151,12 @@ fn format(input: &str) -> Vec<FormatCommand> {
 #[cfg(test)]
 mod tests {
     use super::Format;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Format {})
+        Ok(test_examples(Format {})?)
     }
 }

crates/nu-cli/src/commands/from.rs

@@ -35,11 +35,12 @@ impl WholeStreamCommand for From {
 #[cfg(test)]
 mod tests {
     use super::From;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(From {})
+        Ok(test_examples(From {})?)
     }
 }

crates/nu-cli/src/commands/from_csv.rs

@@ -109,11 +109,12 @@ async fn from_csv(
 #[cfg(test)]
 mod tests {
     use super::FromCSV;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromCSV {})
+        Ok(test_examples(FromCSV {})?)
     }
 }

crates/nu-cli/src/commands/from_delimited_data.rs

@@ -14,6 +14,7 @@ fn from_delimited_string_to_value(
         .delimiter(separator as u8)
         .from_reader(s.as_bytes());
     let tag = tag.into();
+    let span = tag.span;
 
     let headers = if headerless {
         (1..=reader.headers()?.len())
@@ -30,7 +31,10 @@ fn from_delimited_string_to_value(
             if let Ok(i) = value.parse::<i64>() {
                 tagged_row.insert_value(header, UntaggedValue::int(i).into_value(&tag))
             } else if let Ok(f) = value.parse::<f64>() {
-                tagged_row.insert_value(header, UntaggedValue::decimal(f).into_value(&tag))
+                tagged_row.insert_value(
+                    header,
+                    UntaggedValue::decimal_from_float(f, span).into_value(&tag),
+                )
             } else {
                 tagged_row.insert_value(header, UntaggedValue::string(value).into_value(&tag))
             }

crates/nu-cli/src/commands/from_eml.rs

@@ -130,11 +130,12 @@ async fn from_eml(
 #[cfg(test)]
 mod tests {
     use super::FromEML;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromEML {})
+        Ok(test_examples(FromEML {})?)
     }
 }

crates/nu-cli/src/commands/from_ics.rs

@@ -249,11 +249,12 @@ fn params_to_value(params: Vec<(String, Vec<String>)>, tag: Tag) -> Value {
 #[cfg(test)]
 mod tests {
     use super::FromIcs;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromIcs {})
+        Ok(test_examples(FromIcs {})?)
     }
 }

crates/nu-cli/src/commands/from_ini.rs

@@ -95,11 +95,12 @@ async fn from_ini(
 #[cfg(test)]
 mod tests {
     use super::FromINI;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromINI {})
+        Ok(test_examples(FromINI {})?)
     }
 }

crates/nu-cli/src/commands/from_json.rs

@@ -39,11 +39,12 @@ impl WholeStreamCommand for FromJSON {
 
 fn convert_json_value_to_nu_value(v: &serde_hjson::Value, tag: impl Into<Tag>) -> Value {
     let tag = tag.into();
+    let span = tag.span;
 
     match v {
         serde_hjson::Value::Null => UntaggedValue::Primitive(Primitive::Nothing).into_value(&tag),
         serde_hjson::Value::Bool(b) => UntaggedValue::boolean(*b).into_value(&tag),
-        serde_hjson::Value::F64(n) => UntaggedValue::decimal(*n).into_value(&tag),
+        serde_hjson::Value::F64(n) => UntaggedValue::decimal_from_float(*n, span).into_value(&tag),
         serde_hjson::Value::U64(n) => UntaggedValue::int(*n).into_value(&tag),
         serde_hjson::Value::I64(n) => UntaggedValue::int(*n).into_value(&tag),
         serde_hjson::Value::String(s) => {
@@ -143,11 +144,12 @@ async fn from_json(
 #[cfg(test)]
 mod tests {
     use super::FromJSON;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromJSON {})
+        Ok(test_examples(FromJSON {})?)
     }
 }

crates/nu-cli/src/commands/from_ods.rs

@@ -45,6 +45,7 @@ async fn from_ods(
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
+    let span = tag.span;
     let registry = registry.clone();
 
     let (
@@ -73,7 +74,7 @@ async fn from_ods(
                     let value = match cell {
                         DataType::Empty => UntaggedValue::nothing(),
                         DataType::String(s) => UntaggedValue::string(s),
-                        DataType::Float(f) => UntaggedValue::decimal(*f),
+                        DataType::Float(f) => UntaggedValue::decimal_from_float(*f, span),
                         DataType::Int(i) => UntaggedValue::int(*i),
                         DataType::Bool(b) => UntaggedValue::boolean(*b),
                         _ => UntaggedValue::nothing(),
@@ -101,11 +102,12 @@ async fn from_ods(
 #[cfg(test)]
 mod tests {
     use super::FromODS;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromODS {})
+        Ok(test_examples(FromODS {})?)
     }
 }

crates/nu-cli/src/commands/from_ssv.rs

@@ -135,7 +135,7 @@ fn parse_aligned_columns<'a>(
             .flat_map(|s| find_indices(*s))
             .collect::<Vec<usize>>();
 
-        indices.sort();
+        indices.sort_unstable();
         indices.dedup();
 
         let headers: Vec<(String, usize)> = indices
@@ -302,7 +302,9 @@ async fn from_ssv(
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::*;
+
     fn owned(x: &str, y: &str) -> (String, String) {
         (String::from(x), String::from(y))
     }
@@ -504,10 +506,10 @@ mod tests {
     }
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use super::FromSSV;
         use crate::examples::test as test_examples;
 
-        test_examples(FromSSV {})
+        Ok(test_examples(FromSSV {})?)
     }
 }

crates/nu-cli/src/commands/from_toml.rs

@@ -30,11 +30,12 @@ impl WholeStreamCommand for FromTOML {
 
 pub fn convert_toml_value_to_nu_value(v: &toml::Value, tag: impl Into<Tag>) -> Value {
     let tag = tag.into();
+    let span = tag.span;
 
     match v {
         toml::Value::Boolean(b) => UntaggedValue::boolean(*b).into_value(tag),
         toml::Value::Integer(n) => UntaggedValue::int(*n).into_value(tag),
-        toml::Value::Float(n) => UntaggedValue::decimal(*n).into_value(tag),
+        toml::Value::Float(n) => UntaggedValue::decimal_from_float(*n, span).into_value(tag),
         toml::Value::String(s) => {
             UntaggedValue::Primitive(Primitive::String(String::from(s))).into_value(tag)
         }
@@ -100,11 +101,12 @@ pub async fn from_toml(
 #[cfg(test)]
 mod tests {
     use super::FromTOML;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromTOML {})
+        Ok(test_examples(FromTOML {})?)
     }
 }

crates/nu-cli/src/commands/from_tsv.rs

@@ -52,11 +52,12 @@ async fn from_tsv(
 #[cfg(test)]
 mod tests {
     use super::FromTSV;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromTSV {})
+        Ok(test_examples(FromTSV {})?)
     }
 }

crates/nu-cli/src/commands/from_url.rs

@@ -64,11 +64,12 @@ async fn from_url(
 #[cfg(test)]
 mod tests {
     use super::FromURL;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromURL {})
+        Ok(test_examples(FromURL {})?)
     }
 }

crates/nu-cli/src/commands/from_vcf.rs

@@ -104,11 +104,12 @@ fn params_to_value(params: Vec<(String, Vec<String>)>, tag: Tag) -> Value {
 #[cfg(test)]
 mod tests {
     use super::FromVcf;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromVcf {})
+        Ok(test_examples(FromVcf {})?)
     }
 }

crates/nu-cli/src/commands/from_xlsx.rs

@@ -45,6 +45,7 @@ async fn from_xlsx(
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
+    let span = tag.span;
     let registry = registry.clone();
     let (
         FromXLSXArgs {
@@ -73,7 +74,7 @@ async fn from_xlsx(
                     let value = match cell {
                         DataType::Empty => UntaggedValue::nothing(),
                         DataType::String(s) => UntaggedValue::string(s),
-                        DataType::Float(f) => UntaggedValue::decimal(*f),
+                        DataType::Float(f) => UntaggedValue::decimal_from_float(*f, span),
                         DataType::Int(i) => UntaggedValue::int(*i),
                         DataType::Bool(b) => UntaggedValue::boolean(*b),
                         _ => UntaggedValue::nothing(),
@@ -101,11 +102,12 @@ async fn from_xlsx(
 #[cfg(test)]
 mod tests {
     use super::FromXLSX;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromXLSX {})
+        Ok(test_examples(FromXLSX {})?)
     }
 }

crates/nu-cli/src/commands/from_xml.rs

@@ -135,6 +135,7 @@ async fn from_xml(
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use crate::commands::from_xml;
     use indexmap::IndexMap;
     use nu_protocol::{UntaggedValue, Value};
@@ -304,10 +305,10 @@ mod tests {
     }
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use super::FromXML;
         use crate::examples::test as test_examples;
 
-        test_examples(FromXML {})
+        Ok(test_examples(FromXML {})?)
     }
 }

crates/nu-cli/src/commands/from_yaml.rs

@@ -58,6 +58,7 @@ fn convert_yaml_value_to_nu_value(
     tag: impl Into<Tag>,
 ) -> Result<Value, ShellError> {
     let tag = tag.into();
+    let span = tag.span;
 
     let err_not_compatible_number = ShellError::labeled_error(
         "Expected a compatible number",
@@ -69,10 +70,11 @@ fn convert_yaml_value_to_nu_value(
         serde_yaml::Value::Number(n) if n.is_i64() => {
             UntaggedValue::int(n.as_i64().ok_or_else(|| err_not_compatible_number)?).into_value(tag)
         }
-        serde_yaml::Value::Number(n) if n.is_f64() => {
-            UntaggedValue::decimal(n.as_f64().ok_or_else(|| err_not_compatible_number)?)
-                .into_value(tag)
-        }
+        serde_yaml::Value::Number(n) if n.is_f64() => UntaggedValue::decimal_from_float(
+            n.as_f64().ok_or_else(|| err_not_compatible_number)?,
+            span,
+        )
+        .into_value(tag),
         serde_yaml::Value::String(s) => UntaggedValue::string(s).into_value(tag),
         serde_yaml::Value::Sequence(a) => {
             let result: Result<Vec<Value>, ShellError> = a
@@ -171,15 +173,16 @@ async fn from_yaml(
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::*;
     use nu_plugin::row;
     use nu_plugin::test_helpers::value::string;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(FromYAML {})
+        Ok(test_examples(FromYAML {})?)
     }
 
     #[test]

crates/nu-cli/src/commands/get.rs

@@ -4,8 +4,8 @@ use indexmap::set::IndexSet;
 use log::trace;
 use nu_errors::ShellError;
 use nu_protocol::{
-    did_you_mean, ColumnPath, PathMember, Primitive, ReturnSuccess, Signature, SyntaxShape,
-    UnspannedPathMember, UntaggedValue, Value,
+    did_you_mean, ColumnPath, Dictionary, PathMember, Primitive, ReturnSuccess, Signature,
+    SyntaxShape, UnspannedPathMember, UntaggedValue, Value,
 };
 use nu_source::HasFallibleSpan;
 use nu_value_ext::get_data_by_column_path;
@@ -58,206 +58,221 @@ impl WholeStreamCommand for Get {
     }
 }
 
-pub fn get_column_path(path: &ColumnPath, obj: &Value) -> Result<Value, ShellError> {
-    let fields = path.clone();
-
-    get_data_by_column_path(
-        obj,
-        path,
-        Box::new(move |(obj_source, column_path_tried, error)| {
-            let path_members_span = fields.maybe_span().unwrap_or_else(Span::unknown);
-
-            match &obj_source.value {
-                UntaggedValue::Table(rows) => match column_path_tried {
-                    PathMember {
-                        unspanned: UnspannedPathMember::String(column),
-                        ..
-                    } => {
-                        let primary_label = format!("There isn't a column named '{}'", &column);
-
-                        let suggestions: IndexSet<_> = rows
-                            .iter()
-                            .filter_map(|r| did_you_mean(&r, &column_path_tried))
-                            .map(|s| s[0].1.to_owned())
-                            .collect();
-                        let mut existing_columns: IndexSet<_> = IndexSet::default();
-                        let mut names: Vec<String> = vec![];
-
-                        for row in rows {
-                            for field in row.data_descriptors() {
-                                if !existing_columns.contains(&field[..]) {
-                                    existing_columns.insert(field.clone());
-                                    names.push(field);
-                                }
-                            }
-                        }
-
-                        if names.is_empty() {
-                            return ShellError::labeled_error_with_secondary(
-                                "Unknown column",
-                                primary_label,
-                                column_path_tried.span,
-                                "Appears to contain rows. Try indexing instead.",
-                                column_path_tried.span.since(path_members_span),
-                            );
-                        } else {
-                            return ShellError::labeled_error_with_secondary(
-                                "Unknown column",
-                                primary_label,
-                                column_path_tried.span,
-                                format!(
-                                    "Perhaps you meant '{}'? Columns available: {}",
-                                    suggestions
-                                        .iter()
-                                        .map(|x| x.to_owned())
-                                        .collect::<Vec<String>>()
-                                        .join(","),
-                                    names.join(",")
-                                ),
-                                column_path_tried.span.since(path_members_span),
-                            );
-                        };
-                    }
-                    PathMember {
-                        unspanned: UnspannedPathMember::Int(idx),
-                        ..
-                    } => {
-                        let total = rows.len();
-
-                        let secondary_label = if total == 1 {
-                            "The table only has 1 row".to_owned()
-                        } else {
-                            format!("The table only has {} rows (0 to {})", total, total - 1)
-                        };
-
-                        return ShellError::labeled_error_with_secondary(
-                            "Row not found",
-                            format!("There isn't a row indexed at {}", idx),
-                            column_path_tried.span,
-                            secondary_label,
-                            column_path_tried.span.since(path_members_span),
-                        );
-                    }
-                },
-                UntaggedValue::Row(columns) => match column_path_tried {
-                    PathMember {
-                        unspanned: UnspannedPathMember::String(column),
-                        ..
-                    } => {
-                        let primary_label = format!("There isn't a column named '{}'", &column);
-
-                        if let Some(suggestions) = did_you_mean(&obj_source, column_path_tried) {
-                            return ShellError::labeled_error_with_secondary(
-                                "Unknown column",
-                                primary_label,
-                                column_path_tried.span,
-                                format!(
-                                    "Perhaps you meant '{}'? Columns available: {}",
-                                    suggestions[0].1,
-                                    &obj_source.data_descriptors().join(",")
-                                ),
-                                column_path_tried.span.since(path_members_span),
-                            );
-                        }
-                    }
-                    PathMember {
-                        unspanned: UnspannedPathMember::Int(idx),
-                        ..
-                    } => {
-                        return ShellError::labeled_error_with_secondary(
-                            "No rows available",
-                            format!("A row at '{}' can't be indexed.", &idx),
-                            column_path_tried.span,
-                            format!(
-                                "Appears to contain columns. Columns available: {}",
-                                columns.keys().join(",")
-                            ),
-                            column_path_tried.span.since(path_members_span),
-                        )
-                    }
-                },
-                _ => {}
-            }
-
-            if let Some(suggestions) = did_you_mean(&obj_source, column_path_tried) {
-                return ShellError::labeled_error(
-                    "Unknown column",
-                    format!("did you mean '{}'?", suggestions[0].1),
-                    column_path_tried.span.since(path_members_span),
-                );
-            }
-
-            error
-        }),
-    )
-}
-
 pub async fn get(
     args: CommandArgs,
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
     let registry = registry.clone();
-    let (GetArgs { rest: mut fields }, mut input) = args.process(&registry).await?;
-    if fields.is_empty() {
+    let (GetArgs { rest: column_paths }, mut input) = args.process(&registry).await?;
+    if column_paths.is_empty() {
         let vec = input.drain_vec().await;
 
         let descs = nu_protocol::merge_descriptors(&vec);
 
         Ok(futures::stream::iter(descs.into_iter().map(ReturnSuccess::value)).to_output_stream())
     } else {
-        let member = fields.remove(0);
-        trace!("get {:?} {:?}", member, fields);
-
-        Ok(input
+        trace!("get {:?}", column_paths);
+        let output_stream = input
             .map(move |item| {
-                let member = vec![member.clone()];
-
-                let column_paths = vec![&member, &fields]
-                    .into_iter()
+                let output = column_paths
+                    .iter()
+                    .map(move |path| get_output(&item, path))
                     .flatten()
-                    .collect::<Vec<&ColumnPath>>();
-
-                let mut output = vec![];
-                for path in column_paths {
-                    let res = get_column_path(&path, &item);
-
-                    match res {
-                        Ok(got) => match got {
-                            Value {
-                                value: UntaggedValue::Table(rows),
-                                ..
-                            } => {
-                                for item in rows {
-                                    output.push(ReturnSuccess::value(item.clone()));
-                                }
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Nothing),
-                                ..
-                            } => {}
-                            other => output.push(ReturnSuccess::value(other.clone())),
-                        },
-                        Err(reason) => output.push(ReturnSuccess::value(
-                            UntaggedValue::Error(reason).into_untagged_value(),
-                        )),
-                    }
-                }
-
+                    .collect::<Vec<_>>();
                 futures::stream::iter(output)
             })
             .flatten()
-            .to_output_stream())
+            .to_output_stream();
+        Ok(output_stream)
+    }
+}
+
+fn get_output(item: &Value, path: &ColumnPath) -> Vec<Result<ReturnSuccess, ShellError>> {
+    match get_column_path(path, item) {
+        Ok(Value {
+            value: UntaggedValue::Primitive(Primitive::Nothing),
+            ..
+        }) => vec![],
+        Ok(Value {
+            value: UntaggedValue::Table(rows),
+            ..
+        }) => rows.into_iter().map(ReturnSuccess::value).collect(),
+        Ok(other) => vec![ReturnSuccess::value(other)],
+        Err(reason) => vec![ReturnSuccess::value(
+            UntaggedValue::Error(reason).into_untagged_value(),
+        )],
+    }
+}
+
+pub fn get_column_path(path: &ColumnPath, obj: &Value) -> Result<Value, ShellError> {
+    get_data_by_column_path(obj, path, move |obj_source, column_path_tried, error| {
+        let path_members_span = path.maybe_span().unwrap_or_else(Span::unknown);
+
+        match &obj_source.value {
+            UntaggedValue::Table(rows) => {
+                return get_column_path_from_table_error(
+                    rows,
+                    column_path_tried,
+                    &path_members_span,
+                );
+            }
+            UntaggedValue::Row(columns) => {
+                if let Some(error) = get_column_from_row_error(
+                    columns,
+                    column_path_tried,
+                    &path_members_span,
+                    obj_source,
+                ) {
+                    return error;
+                }
+            }
+            _ => {}
+        }
+
+        if let Some(suggestions) = did_you_mean(&obj_source, column_path_tried.as_string()) {
+            ShellError::labeled_error(
+                "Unknown column",
+                format!("did you mean '{}'?", suggestions[0]),
+                column_path_tried.span.since(path_members_span),
+            )
+        } else {
+            error
+        }
+    })
+}
+
+pub fn get_column_path_from_table_error(
+    rows: &[Value],
+    column_path_tried: &PathMember,
+    path_members_span: &Span,
+) -> ShellError {
+    match column_path_tried {
+        PathMember {
+            unspanned: UnspannedPathMember::String(column),
+            ..
+        } => {
+            let primary_label = format!("There isn't a column named '{}'", &column);
+
+            let suggestions: IndexSet<_> = rows
+                .iter()
+                .filter_map(|r| did_you_mean(&r, column_path_tried.as_string()))
+                .map(|s| s[0].to_owned())
+                .collect();
+            let mut existing_columns: IndexSet<_> = IndexSet::default();
+            let mut names: Vec<String> = vec![];
+
+            for row in rows {
+                for field in row.data_descriptors() {
+                    if !existing_columns.contains(&field[..]) {
+                        existing_columns.insert(field.clone());
+                        names.push(field);
+                    }
+                }
+            }
+
+            if names.is_empty() {
+                ShellError::labeled_error_with_secondary(
+                    "Unknown column",
+                    primary_label,
+                    column_path_tried.span,
+                    "Appears to contain rows. Try indexing instead.",
+                    column_path_tried.span.since(path_members_span),
+                )
+            } else {
+                ShellError::labeled_error_with_secondary(
+                    "Unknown column",
+                    primary_label,
+                    column_path_tried.span,
+                    format!(
+                        "Perhaps you meant '{}'? Columns available: {}",
+                        suggestions
+                            .iter()
+                            .map(|x| x.to_owned())
+                            .collect::<Vec<String>>()
+                            .join(","),
+                        names.join(", ")
+                    ),
+                    column_path_tried.span.since(path_members_span),
+                )
+            }
+        }
+        PathMember {
+            unspanned: UnspannedPathMember::Int(idx),
+            ..
+        } => {
+            let total = rows.len();
+
+            let secondary_label = if total == 1 {
+                "The table only has 1 row".to_owned()
+            } else {
+                format!("The table only has {} rows (0 to {})", total, total - 1)
+            };
+
+            ShellError::labeled_error_with_secondary(
+                "Row not found",
+                format!("There isn't a row indexed at {}", idx),
+                column_path_tried.span,
+                secondary_label,
+                column_path_tried.span.since(path_members_span),
+            )
+        }
+    }
+}
+
+pub fn get_column_from_row_error(
+    columns: &Dictionary,
+    column_path_tried: &PathMember,
+    path_members_span: &Span,
+    obj_source: &Value,
+) -> Option<ShellError> {
+    match column_path_tried {
+        PathMember {
+            unspanned: UnspannedPathMember::String(column),
+            ..
+        } => {
+            let primary_label = format!("There isn't a column named '{}'", &column);
+
+            if let Some(suggestions) = did_you_mean(&obj_source, column_path_tried.as_string()) {
+                Some(ShellError::labeled_error_with_secondary(
+                    "Unknown column",
+                    primary_label,
+                    column_path_tried.span,
+                    format!(
+                        "Perhaps you meant '{}'? Columns available: {}",
+                        suggestions[0],
+                        &obj_source.data_descriptors().join(", ")
+                    ),
+                    column_path_tried.span.since(path_members_span),
+                ))
+            } else {
+                None
+            }
+        }
+        PathMember {
+            unspanned: UnspannedPathMember::Int(idx),
+            ..
+        } => Some(ShellError::labeled_error_with_secondary(
+            "No rows available",
+            format!("A row at '{}' can't be indexed.", &idx),
+            column_path_tried.span,
+            format!(
+                "Appears to contain columns. Columns available: {}",
+                columns.keys().join(", ")
+            ),
+            column_path_tried.span.since(path_members_span),
+        )),
     }
 }
 
 #[cfg(test)]
 mod tests {
     use super::Get;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Get {})
+        Ok(test_examples(Get {})?)
     }
 }

crates/nu-cli/src/commands/group_by.rs

@@ -1,20 +1,21 @@
 use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
+use crate::utils::suggestions::suggestions;
 use indexmap::indexmap;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 use nu_source::Tagged;
 use nu_value_ext::as_string;
 
-pub struct GroupBy;
+pub struct Command;
 
 #[derive(Deserialize)]
-pub struct GroupByArgs {
+pub struct Arguments {
     grouper: Option<Value>,
 }
 
 #[async_trait]
-impl WholeStreamCommand for GroupBy {
+impl WholeStreamCommand for Command {
     fn name(&self) -> &str {
         "group-by"
     }
@@ -28,7 +29,7 @@ impl WholeStreamCommand for GroupBy {
     }
 
     fn usage(&self) -> &str {
-        "create a new table grouped."
+        "Create a new table grouped."
     }
 
     async fn run(
@@ -39,17 +40,45 @@ impl WholeStreamCommand for GroupBy {
         group_by(args, registry).await
     }
 
+    #[allow(clippy::unwrap_used)]
     fn examples(&self) -> Vec<Example> {
+        use nu_data::value::date_naive_from_str as date;
+
         vec![
             Example {
                 description: "group items by column named \"type\"",
                 example: r#"ls | group-by type"#,
-                result: None,
-            },
-            Example {
-                description: "blocks can be used for generating a grouping key (same as above)",
-                example: r#"ls | group-by { get type }"#,
-                result: None,
+                result: Some(vec![UntaggedValue::row(indexmap! {
+                    "File".to_string() => UntaggedValue::Table(vec![
+                        UntaggedValue::row(indexmap! {
+                            "modified".to_string() => date("2019-07-23".tagged_unknown()).unwrap().into(),
+                                "name".to_string() =>          UntaggedValue::string("Andrés.txt").into(),
+                                "type".to_string() =>                UntaggedValue::string("File").into(),
+                            "chickens".to_string() =>                       UntaggedValue::int(10).into(),
+                        }).into(),
+                        UntaggedValue::row(indexmap! {
+                            "modified".to_string() => date("2019-09-24".tagged_unknown()).unwrap().into(),
+                                "name".to_string() =>          UntaggedValue::string("Andrés.txt").into(),
+                                "type".to_string() =>                UntaggedValue::string("File").into(),
+                            "chickens".to_string() =>                       UntaggedValue::int(20).into(),
+                        }).into(),
+                    ]).into(),
+                    "Dir".to_string() => UntaggedValue::Table(vec![
+                        UntaggedValue::row(indexmap! {
+                            "modified".to_string() => date("2019-07-23".tagged_unknown()).unwrap().into(),
+                                "name".to_string() =>            UntaggedValue::string("Jonathan").into(),
+                                "type".to_string() =>                 UntaggedValue::string("Dir").into(),
+                            "chickens".to_string() =>                        UntaggedValue::int(5).into(),
+                        }).into(),
+                        UntaggedValue::row(indexmap! {
+                            "modified".to_string() => date("2019-09-24".tagged_unknown()).unwrap().into(),
+                                "name".to_string() =>              UntaggedValue::string("Yehuda").into(),
+                                "type".to_string() =>                 UntaggedValue::string("Dir").into(),
+                            "chickens".to_string() =>                        UntaggedValue::int(4).into(),
+                        }).into(),
+                    ]).into(),
+                })
+                .into()]),
             },
             Example {
                 description: "you can also group by raw values by leaving out the argument",
@@ -74,10 +103,26 @@ impl WholeStreamCommand for GroupBy {
                 .into()]),
             },
             Example {
-                description: "write pipelines for a more involved grouping key",
-                example:
-                    "echo [1 3 1 3 2 1 1] | group-by { echo `({{$it}} - 1) % 3` | calc | str from }",
-                result: None,
+                description:
+                    "use the block form to generate a grouping key when each row gets processed",
+                example: "echo [1 3 1 3 2 1 1] | group-by { = ($it - 1) mod 3 }",
+                result: Some(vec![UntaggedValue::row(indexmap! {
+                    "0".to_string() => UntaggedValue::Table(vec![
+                        UntaggedValue::int(1).into(),
+                        UntaggedValue::int(1).into(),
+                        UntaggedValue::int(1).into(),
+                        UntaggedValue::int(1).into(),
+
+                    ]).into(),
+                    "2".to_string() => UntaggedValue::Table(vec![
+                        UntaggedValue::int(3).into(),
+                        UntaggedValue::int(3).into(),
+                    ]).into(),
+                    "1".to_string() => UntaggedValue::Table(vec![
+                        UntaggedValue::int(2).into(),
+                    ]).into(),
+                })
+                .into()]),
             },
         ]
     }
@@ -95,9 +140,9 @@ pub async fn group_by(
     let name = args.call_info.name_tag.clone();
     let registry = registry.clone();
     let head = Arc::new(args.call_info.args.head.clone());
-    let scope = Arc::new(args.call_info.scope.clone());
-    let context = Arc::new(Context::from_raw(&args, &registry));
-    let (GroupByArgs { grouper }, input) = args.process(&registry).await?;
+    let scope = args.call_info.scope.clone();
+    let context = Arc::new(EvaluationContext::from_raw(&args, &registry));
+    let (Arguments { grouper }, input) = args.process(&registry).await?;
 
     let values: Vec<Value> = input.collect().await;
     let mut keys: Vec<Result<String, ShellError>> = vec![];
@@ -167,6 +212,14 @@ pub async fn group_by(
         ));
     }
 
+    let first = values[0].clone();
+
+    let name = if first.tag.anchor().is_some() {
+        first.tag
+    } else {
+        name
+    };
+
     let values = UntaggedValue::table(&values).into_value(&name);
 
     let group_value = match group_strategy {
@@ -179,39 +232,14 @@ pub async fn group_by(
                 None => as_string(row),
             });
 
-            nu_data::utils::group(&values, &Some(block), &name)
+            nu_data::utils::group(&values, &Some(block), name)
         }
-        Grouper::ByColumn(column_name) => group(&column_name, &values, name),
+        Grouper::ByColumn(column_name) => group(&column_name, &values, &name),
     };
 
     Ok(OutputStream::one(ReturnSuccess::value(group_value?)))
 }
 
-pub fn suggestions(tried: Tagged<&str>, for_value: &Value) -> ShellError {
-    let possibilities = for_value.data_descriptors();
-
-    let mut possible_matches: Vec<_> = possibilities
-        .iter()
-        .map(|x| (natural::distance::levenshtein_distance(x, &tried), x))
-        .collect();
-
-    possible_matches.sort();
-
-    if !possible_matches.is_empty() {
-        ShellError::labeled_error(
-            "Unknown column",
-            format!("did you mean '{}'?", possible_matches[0].1),
-            tried.tag(),
-        )
-    } else {
-        ShellError::labeled_error(
-            "Unknown column",
-            "row does not contain this column",
-            tried.tag(),
-        )
-    }
-}
-
 pub fn group(
     column_name: &Option<Tagged<String>>,
     values: &Value,
@@ -311,12 +339,4 @@ mod tests {
 
         Ok(())
     }
-
-    #[test]
-    fn examples_work_as_expected() {
-        use super::GroupBy;
-        use crate::examples::test as test_examples;
-
-        test_examples(GroupBy {})
-    }
 }

crates/nu-cli/src/commands/group_by_date.rs

@@ -1,5 +1,6 @@
 use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
+use crate::utils::suggestions::suggestions;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 use nu_source::Tagged;
@@ -137,39 +138,15 @@ pub async fn group_by_date(
     }
 }
 
-pub fn suggestions(tried: Tagged<&str>, for_value: &Value) -> ShellError {
-    let possibilities = for_value.data_descriptors();
-
-    let mut possible_matches: Vec<_> = possibilities
-        .iter()
-        .map(|x| (natural::distance::levenshtein_distance(x, &tried), x))
-        .collect();
-
-    possible_matches.sort();
-
-    if !possible_matches.is_empty() {
-        ShellError::labeled_error(
-            "Unknown column",
-            format!("did you mean '{}'?", possible_matches[0].1),
-            tried.tag(),
-        )
-    } else {
-        ShellError::labeled_error(
-            "Unknown column",
-            "row does not contain this column",
-            tried.tag(),
-        )
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::GroupByDate;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(GroupByDate {})
+        Ok(test_examples(GroupByDate {})?)
     }
 }

crates/nu-cli/src/commands/headers.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use futures::stream::StreamExt;
 use indexmap::IndexMap;
@@ -116,11 +116,12 @@ pub async fn headers(
 #[cfg(test)]
 mod tests {
     use super::Headers;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Headers {})
+        Ok(test_examples(Headers {})?)
     }
 }

crates/nu-cli/src/commands/help.rs

@@ -6,7 +6,7 @@ use nu_data::command::signature_dict;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, TaggedDictBuilder, UntaggedValue, Value};
 use nu_source::{SpannedItem, Tagged};
-use nu_value_ext::get_data_by_key;
+use nu_value_ext::ValueExt;
 
 pub struct Help;
 
@@ -63,54 +63,115 @@ async fn help(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStr
             let mut sorted_names = registry.names();
             sorted_names.sort();
 
-            Ok(
-                futures::stream::iter(sorted_names.into_iter().filter_map(move |cmd| {
-                    // If it's a subcommand, don't list it during the commands list
-                    if cmd.contains(' ') {
-                        return None;
-                    }
-                    let mut short_desc = TaggedDictBuilder::new(name.clone());
-                    let document_tag = rest[0].tag.clone();
-                    let value = command_dict(
-                        match registry.get_command(&cmd).ok_or_else(|| {
+            let (mut subcommand_names, command_names) = sorted_names
+                .into_iter()
+                // Internal only commands shouldn't be displayed
+                .filter(|cmd_name| {
+                    registry
+                        .get_command(&cmd_name)
+                        .filter(|command| !command.is_internal())
+                        .is_some()
+                })
+                .partition::<Vec<_>, _>(|cmd_name| cmd_name.contains(' '));
+
+            fn process_name(
+                dict: &mut TaggedDictBuilder,
+                cmd_name: &str,
+                registry: CommandRegistry,
+                rest: Vec<Tagged<String>>,
+                name: Tag,
+            ) -> Result<(), ShellError> {
+                let document_tag = rest[0].tag.clone();
+                let value = command_dict(
+                    registry.get_command(&cmd_name).ok_or_else(|| {
+                        ShellError::labeled_error(
+                            format!("Could not load {}", cmd_name),
+                            "could not load command",
+                            document_tag,
+                        )
+                    })?,
+                    name,
+                );
+
+                dict.insert_untagged("name", cmd_name);
+                dict.insert_untagged(
+                    "description",
+                    value
+                        .get_data_by_key("usage".spanned_unknown())
+                        .ok_or_else(|| {
                             ShellError::labeled_error(
-                                format!("Could not load {}", cmd),
-                                "could not load command",
-                                document_tag,
+                                "Expected a usage key",
+                                "expected a 'usage' key",
+                                &value.tag,
                             )
-                        }) {
-                            Ok(ok) => ok,
-                            Err(err) => return Some(Err(err)),
-                        },
-                        name.clone(),
-                    );
+                        })?
+                        .as_string()?,
+                );
 
-                    short_desc.insert_untagged("name", cmd);
-                    short_desc.insert_untagged(
-                        "description",
-                        match match get_data_by_key(&value, "usage".spanned_unknown()).ok_or_else(
-                            || {
-                                ShellError::labeled_error(
-                                    "Expected a usage key",
-                                    "expected a 'usage' key",
-                                    &value.tag,
-                                )
-                            },
-                        ) {
-                            Ok(ok) => ok,
-                            Err(err) => return Some(Err(err)),
-                        }
-                        .as_string()
-                        {
-                            Ok(ok) => ok,
-                            Err(err) => return Some(Err(err)),
-                        },
-                    );
+                Ok(())
+            }
 
-                    Some(ReturnSuccess::value(short_desc.into_value()))
-                }))
-                .to_output_stream(),
-            )
+            fn make_subcommands_table(
+                subcommand_names: &mut Vec<String>,
+                cmd_name: &str,
+                registry: CommandRegistry,
+                rest: Vec<Tagged<String>>,
+                name: Tag,
+            ) -> Result<Value, ShellError> {
+                let (matching, not_matching) =
+                    subcommand_names.drain(..).partition(|subcommand_name| {
+                        subcommand_name.starts_with(&format!("{} ", cmd_name))
+                    });
+                *subcommand_names = not_matching;
+                Ok(if !matching.is_empty() {
+                    UntaggedValue::table(
+                        &(matching
+                            .into_iter()
+                            .map(|cmd_name: String| -> Result<_, ShellError> {
+                                let mut short_desc = TaggedDictBuilder::new(name.clone());
+                                process_name(
+                                    &mut short_desc,
+                                    &cmd_name,
+                                    registry.clone(),
+                                    rest.clone(),
+                                    name.clone(),
+                                )?;
+                                Ok(short_desc.into_value())
+                            })
+                            .collect::<Result<Vec<_>, _>>()?[..]),
+                    )
+                    .into_value(name)
+                } else {
+                    UntaggedValue::nothing().into_value(name)
+                })
+            }
+
+            let iterator =
+                command_names
+                    .into_iter()
+                    .map(move |cmd_name| -> Result<_, ShellError> {
+                        let mut short_desc = TaggedDictBuilder::new(name.clone());
+                        process_name(
+                            &mut short_desc,
+                            &cmd_name,
+                            registry.clone(),
+                            rest.clone(),
+                            name.clone(),
+                        )?;
+                        short_desc.insert_value(
+                            "subcommands",
+                            make_subcommands_table(
+                                &mut subcommand_names,
+                                &cmd_name,
+                                registry.clone(),
+                                rest.clone(),
+                                name.clone(),
+                            )?,
+                        );
+                        ReturnSuccess::value(short_desc.into_value())
+                    });
+
+            Ok(futures::stream::iter(iterator).to_output_stream())
         } else if rest[0].item == "generate_docs" {
             Ok(OutputStream::one(ReturnSuccess::value(generate_docs(
                 &registry,
@@ -174,11 +235,12 @@ pub fn get_help(cmd: &dyn WholeStreamCommand, registry: &CommandRegistry) -> Str
 #[cfg(test)]
 mod tests {
     use super::Help;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Help {})
+        Ok(test_examples(Help {})?)
     }
 }

crates/nu-cli/src/commands/histogram.rs

@@ -112,8 +112,9 @@ pub async fn histogram(
         nu_data::utils::Operation {
             grouper: Some(Box::new(move |_, _| Ok(String::from("frequencies")))),
             splitter: Some(splitter(column_grouper)),
-            format: None,
+            format: &None,
             eval: &evaluate_with,
+            reduction: &nu_data::utils::Reduction::Count,
         },
         &name,
     )?;
@@ -123,17 +124,33 @@ pub async fn histogram(
 
     Ok(futures::stream::iter(
         results
-            .percentages
+            .data
             .table_entries()
-            .map(move |value| {
-                let values = value.table_entries().cloned().collect::<Vec<_>>();
-                let occurrences = values.len();
-
-                (occurrences, values[occurrences - 1].clone())
-            })
+            .cloned()
             .collect::<Vec<_>>()
             .into_iter()
-            .map(move |(occurrences, value)| {
+            .zip(
+                results
+                    .percentages
+                    .table_entries()
+                    .cloned()
+                    .collect::<Vec<_>>()
+                    .into_iter(),
+            )
+            .map(move |(counts, percentages)| {
+                let percentage = percentages
+                    .table_entries()
+                    .cloned()
+                    .last()
+                    .unwrap_or_else(|| {
+                        UntaggedValue::decimal_from_float(0.0, name.span).into_value(&name)
+                    });
+                let value = counts
+                    .table_entries()
+                    .cloned()
+                    .last()
+                    .unwrap_or_else(|| UntaggedValue::int(0).into_value(&name));
+
                 let mut fact = TaggedDictBuilder::new(&name);
                 let column_value = labels
                     .get(idx)
@@ -147,19 +164,19 @@ pub async fn histogram(
                     .clone();
 
                 fact.insert_value(&column.item, column_value);
-                fact.insert_untagged("occurrences", UntaggedValue::int(occurrences));
+                fact.insert_untagged("count", value);
 
-                let percentage = format!(
+                let fmt_percentage = format!(
                     "{}%",
                     // Some(2) < the number of digits
                     // true < group the digits
-                    crate::commands::str_::from::action(&value, &name, Some(2), true)?
+                    crate::commands::str_::from::action(&percentage, &name, Some(2), true)?
                         .as_string()?
                 );
-                fact.insert_untagged("percentage", UntaggedValue::string(percentage));
+                fact.insert_untagged("percentage", UntaggedValue::string(fmt_percentage));
 
                 let string = std::iter::repeat("*")
-                    .take(value.as_u64().map_err(|_| {
+                    .take(percentage.as_u64().map_err(|_| {
                         ShellError::labeled_error("expected a number", "expected a number", &name)
                     })? as usize)
                     .collect::<String>();
@@ -178,11 +195,7 @@ fn evaluator(by: ColumnPath) -> Box<dyn Fn(usize, &Value) -> Result<Value, Shell
     Box::new(move |_: usize, value: &Value| {
         let path = by.clone();
 
-        let eval = nu_value_ext::get_data_by_column_path(
-            value,
-            &path,
-            Box::new(move |(_, _, error)| error),
-        );
+        let eval = nu_value_ext::get_data_by_column_path(value, &path, move |_, _, error| error);
 
         match eval {
             Ok(with_value) => Ok(with_value),
@@ -214,11 +227,12 @@ fn splitter(
 #[cfg(test)]
 mod tests {
     use super::Histogram;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Histogram {})
+        Ok(test_examples(Histogram {})?)
     }
 }

crates/nu-cli/src/commands/history.rs

@@ -1,6 +1,6 @@
 use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
-use nu_data::config::NuConfig;
+use nu_data::config::{Conf, NuConfig};
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
 use std::fs::File;
@@ -9,9 +9,7 @@ use std::path::PathBuf;
 
 const DEFAULT_LOCATION: &str = "history.txt";
 
-pub fn history_path(config: &NuConfig) -> PathBuf {
-    let vars = config.vars.lock();
-
+pub fn history_path(config: &dyn Conf) -> PathBuf {
     let default_path = nu_data::config::user_data()
         .map(|mut p| {
             p.push(DEFAULT_LOCATION);
@@ -19,7 +17,8 @@ pub fn history_path(config: &NuConfig) -> PathBuf {
         })
         .unwrap_or_else(|_| PathBuf::from(DEFAULT_LOCATION));
 
-    vars.get("history-path")
+    config
+        .var("history-path")
         .map_or(default_path.clone(), |custom_path| {
             match custom_path.as_string() {
                 Ok(path) => PathBuf::from(path),
@@ -54,7 +53,7 @@ impl WholeStreamCommand for History {
 }
 
 fn history(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
-    let config = NuConfig::new();
+    let config: Box<dyn Conf> = Box::new(NuConfig::new());
     let tag = args.call_info.name_tag;
     let path = history_path(&config);
     let file = File::open(path);
@@ -80,11 +79,12 @@ fn history(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStrea
 #[cfg(test)]
 mod tests {
     use super::History;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(History {})
+        Ok(test_examples(History {})?)
     }
 }

crates/nu-cli/src/commands/if_.rs

@@ -1,10 +1,12 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::classified::block::run_block;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::evaluate::evaluate_baseline_expr;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{hir::Block, hir::ClassifiedCommand, Signature, SyntaxShape, UntaggedValue};
+use nu_protocol::{
+    hir::Block, hir::ClassifiedCommand, Scope, Signature, SyntaxShape, UntaggedValue,
+};
 
 pub struct If;
 
@@ -72,9 +74,9 @@ async fn if_command(
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
     let registry = Arc::new(registry.clone());
-    let scope = Arc::new(raw_args.call_info.scope.clone());
+    let scope = raw_args.call_info.scope.clone();
     let tag = raw_args.call_info.name_tag.clone();
-    let context = Arc::new(Context::from_raw(&raw_args, &registry));
+    let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
 
     let (
         IfArgs {
@@ -119,14 +121,12 @@ async fn if_command(
             let then_case = then_case.clone();
             let else_case = else_case.clone();
             let registry = registry.clone();
-            let scope = scope.clone();
+            let scope = Scope::append_it(scope.clone(), input);
             let mut context = context.clone();
 
             async move {
                 //FIXME: should we use the scope that's brought in as well?
-                let condition =
-                    evaluate_baseline_expr(&condition, &*registry, &input, &scope.vars, &scope.env)
-                        .await;
+                let condition = evaluate_baseline_expr(&condition, &*registry, scope.clone()).await;
 
                 match condition {
                     Ok(condition) => match condition.as_bool() {
@@ -136,9 +136,7 @@ async fn if_command(
                                     &then_case,
                                     Arc::make_mut(&mut context),
                                     InputStream::empty(),
-                                    &input,
-                                    &scope.vars,
-                                    &scope.env,
+                                    scope,
                                 )
                                 .await
                                 {
@@ -151,9 +149,7 @@ async fn if_command(
                                     &else_case,
                                     Arc::make_mut(&mut context),
                                     InputStream::empty(),
-                                    &input,
-                                    &scope.vars,
-                                    &scope.env,
+                                    scope,
                                 )
                                 .await
                                 {
@@ -178,11 +174,12 @@ async fn if_command(
 #[cfg(test)]
 mod tests {
     use super::If;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(If {})
+        Ok(test_examples(If {})?)
     }
 }

crates/nu-cli/src/commands/insert.rs

@@ -1,6 +1,6 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::classified::block::run_block;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{
@@ -9,16 +9,18 @@ use nu_protocol::{
 use nu_value_ext::ValueExt;
 
 use futures::stream::once;
-pub struct Insert;
+use indexmap::indexmap;
+
+pub struct Command;
 
 #[derive(Deserialize)]
-pub struct InsertArgs {
+pub struct Arguments {
     column: ColumnPath,
     value: Value,
 }
 
 #[async_trait]
-impl WholeStreamCommand for Insert {
+impl WholeStreamCommand for Command {
     fn name(&self) -> &str {
         "insert"
     }
@@ -44,11 +46,33 @@ impl WholeStreamCommand for Insert {
     ) -> Result<OutputStream, ShellError> {
         insert(args, registry).await
     }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Insert a column with a value",
+            example: "echo [[author, commits]; ['Andrés', 1]] | insert branches 5",
+            result: Some(vec![UntaggedValue::row(indexmap! {
+                    "author".to_string() => Value::from("Andrés"),
+                    "commits".to_string() => UntaggedValue::int(1).into(),
+                    "branches".to_string() => UntaggedValue::int(5).into(),
+            })
+            .into()]),
+        },Example {
+            description: "Use in block form for more involved insertion logic",
+            example: "echo [[author, lucky_number]; ['Yehuda', 4]] | insert success { = $it.lucky_number * 10 }",
+            result: Some(vec![UntaggedValue::row(indexmap! {
+                    "author".to_string() => Value::from("Yehuda"),
+                    "lucky_number".to_string() => UntaggedValue::int(4).into(),
+                    "success".to_string() => UntaggedValue::int(40).into(),
+            })
+            .into()]),
+        }]
+    }
 }
 
 async fn process_row(
     scope: Arc<Scope>,
-    mut context: Arc<Context>,
+    mut context: Arc<EvaluationContext>,
     input: Value,
     mut value: Arc<Value>,
     field: Arc<ColumnPath>,
@@ -63,15 +87,9 @@ async fn process_row(
             let for_block = input.clone();
             let input_stream = once(async { Ok(for_block) }).to_input_stream();
 
-            let result = run_block(
-                &block,
-                Arc::make_mut(&mut context),
-                input_stream,
-                &input,
-                &scope.vars,
-                &scope.env,
-            )
-            .await;
+            let scope = Scope::append_it(scope, input.clone());
+
+            let result = run_block(&block, Arc::make_mut(&mut context), input_stream, scope).await;
 
             match result {
                 Ok(mut stream) => {
@@ -85,13 +103,16 @@ async fn process_row(
                     let result = if values.len() == 1 {
                         let value = values
                             .get(0)
-                            .ok_or_else(|| ShellError::unexpected("No value to insert with"))?;
+                            .ok_or_else(|| ShellError::unexpected("No value to insert with."))?;
 
-                        value.clone()
+                        Value {
+                            value: value.value.clone(),
+                            tag: input.tag.clone(),
+                        }
                     } else if values.is_empty() {
-                        UntaggedValue::nothing().into_untagged_value()
+                        UntaggedValue::nothing().into_value(&input.tag)
                     } else {
-                        UntaggedValue::table(&values).into_untagged_value()
+                        UntaggedValue::table(&values).into_value(&input.tag)
                     };
 
                     match input {
@@ -118,7 +139,11 @@ async fn process_row(
             Value {
                 value: UntaggedValue::Primitive(Primitive::Nothing),
                 ..
-            } => match scope.it.insert_data_at_column_path(&field, value.clone()) {
+            } => match scope
+                .it()
+                .unwrap_or_else(|| UntaggedValue::nothing().into_untagged_value())
+                .insert_data_at_column_path(&field, value.clone())
+            {
                 Ok(v) => OutputStream::one(ReturnSuccess::value(v)),
                 Err(e) => OutputStream::one(Err(e)),
             },
@@ -135,9 +160,9 @@ async fn insert(
     registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
     let registry = registry.clone();
-    let scope = Arc::new(raw_args.call_info.scope.clone());
-    let context = Arc::new(Context::from_raw(&raw_args, &registry));
-    let (InsertArgs { column, value }, input) = raw_args.process(&registry).await?;
+    let scope = raw_args.call_info.scope.clone();
+    let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
+    let (Arguments { column, value }, input) = raw_args.process(&registry).await?;
     let value = Arc::new(value);
     let column = Arc::new(column);
 
@@ -158,15 +183,3 @@ async fn insert(
         .flatten()
         .to_output_stream())
 }
-
-#[cfg(test)]
-mod tests {
-    use super::Insert;
-
-    #[test]
-    fn examples_work_as_expected() {
-        use crate::examples::test as test_examples;
-
-        test_examples(Insert {})
-    }
-}

crates/nu-cli/src/commands/into_int.rs

@@ -78,11 +78,12 @@ async fn into_int(
 #[cfg(test)]
 mod tests {
     use super::IntoInt;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(IntoInt {})
+        Ok(test_examples(IntoInt {})?)
     }
 }

crates/nu-cli/src/commands/is_empty.rs

@@ -1,211 +0,0 @@
-use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
-use crate::prelude::*;
-use nu_errors::ShellError;
-use nu_protocol::{ColumnPath, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
-use nu_source::Tagged;
-use nu_value_ext::ValueExt;
-
-enum IsEmptyFor {
-    Value,
-    RowWithFieldsAndFallback(Vec<Tagged<ColumnPath>>, Value),
-    RowWithField(Tagged<ColumnPath>),
-    RowWithFieldAndFallback(Box<Tagged<ColumnPath>>, Value),
-}
-
-pub struct IsEmpty;
-
-#[derive(Deserialize)]
-pub struct IsEmptyArgs {
-    rest: Vec<Value>,
-}
-
-#[async_trait]
-impl WholeStreamCommand for IsEmpty {
-    fn name(&self) -> &str {
-        "empty?"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("empty?").rest(
-            SyntaxShape::Any,
-            "the names of the columns to check emptiness followed by the replacement value.",
-        )
-    }
-
-    fn usage(&self) -> &str {
-        "Checks emptiness. The last value is the replacement value for any empty column(s) given to check against the table."
-    }
-
-    async fn run(
-        &self,
-        args: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        is_empty(args, registry).await
-    }
-}
-
-async fn is_empty(
-    args: CommandArgs,
-    registry: &CommandRegistry,
-) -> Result<OutputStream, ShellError> {
-    let registry = registry.clone();
-    let (IsEmptyArgs { rest }, input) = args.process(&registry).await?;
-
-    Ok(input
-        .map(move |value| {
-            let value_tag = value.tag();
-
-            let action = if rest.len() <= 2 {
-                let field = rest.get(0);
-                let replacement_if_true = rest.get(1);
-
-                match (field, replacement_if_true) {
-                    (Some(field), Some(replacement_if_true)) => {
-                        IsEmptyFor::RowWithFieldAndFallback(
-                            Box::new(field.as_column_path()?),
-                            replacement_if_true.clone(),
-                        )
-                    }
-                    (Some(field), None) => IsEmptyFor::RowWithField(field.as_column_path()?),
-                    (_, _) => IsEmptyFor::Value,
-                }
-            } else {
-                // let no_args = vec![];
-                let mut arguments = rest.iter().rev();
-                let replacement_if_true = match arguments.next() {
-                    Some(arg) => arg.clone(),
-                    None => UntaggedValue::boolean(value.is_empty()).into_value(&value_tag),
-                };
-
-                IsEmptyFor::RowWithFieldsAndFallback(
-                    arguments
-                        .map(|a| a.as_column_path())
-                        .filter_map(Result::ok)
-                        .collect(),
-                    replacement_if_true,
-                )
-            };
-
-            match action {
-                IsEmptyFor::Value => Ok(ReturnSuccess::Value(
-                    UntaggedValue::boolean(value.is_empty()).into_value(value_tag),
-                )),
-                IsEmptyFor::RowWithFieldsAndFallback(fields, default) => {
-                    let mut out = value;
-
-                    for field in fields.iter() {
-                        let val = crate::commands::get::get_column_path(&field, &out)?;
-
-                        let emptiness_value = match out {
-                            obj
-                            @
-                            Value {
-                                value: UntaggedValue::Row(_),
-                                ..
-                            } => {
-                                if val.is_empty() {
-                                    obj.replace_data_at_column_path(&field, default.clone())
-                                        .ok_or_else(|| {
-                                            ShellError::labeled_error(
-                                                "empty? could not find place to check emptiness",
-                                                "column name",
-                                                &field.tag,
-                                            )
-                                        })
-                                } else {
-                                    Ok(obj)
-                                }
-                            }
-                            _ => Err(ShellError::labeled_error(
-                                "Unrecognized type in stream",
-                                "original value",
-                                &value_tag,
-                            )),
-                        };
-
-                        out = emptiness_value?;
-                    }
-
-                    Ok(ReturnSuccess::Value(out))
-                }
-                IsEmptyFor::RowWithField(field) => {
-                    let val = crate::commands::get::get_column_path(&field, &value)?;
-
-                    match &value {
-                        obj
-                        @
-                        Value {
-                            value: UntaggedValue::Row(_),
-                            ..
-                        } => {
-                            if val.is_empty() {
-                                match obj.replace_data_at_column_path(
-                                    &field,
-                                    UntaggedValue::boolean(true).into_value(&value_tag),
-                                ) {
-                                    Some(v) => Ok(ReturnSuccess::Value(v)),
-                                    None => Err(ShellError::labeled_error(
-                                        "empty? could not find place to check emptiness",
-                                        "column name",
-                                        &field.tag,
-                                    )),
-                                }
-                            } else {
-                                Ok(ReturnSuccess::Value(value))
-                            }
-                        }
-                        _ => Err(ShellError::labeled_error(
-                            "Unrecognized type in stream",
-                            "original value",
-                            &value_tag,
-                        )),
-                    }
-                }
-                IsEmptyFor::RowWithFieldAndFallback(field, default) => {
-                    let val = crate::commands::get::get_column_path(&field, &value)?;
-
-                    match &value {
-                        obj
-                        @
-                        Value {
-                            value: UntaggedValue::Row(_),
-                            ..
-                        } => {
-                            if val.is_empty() {
-                                match obj.replace_data_at_column_path(&field, default) {
-                                    Some(v) => Ok(ReturnSuccess::Value(v)),
-                                    None => Err(ShellError::labeled_error(
-                                        "empty? could not find place to check emptiness",
-                                        "column name",
-                                        &field.tag,
-                                    )),
-                                }
-                            } else {
-                                Ok(ReturnSuccess::Value(value))
-                            }
-                        }
-                        _ => Err(ShellError::labeled_error(
-                            "Unrecognized type in stream",
-                            "original value",
-                            &value_tag,
-                        )),
-                    }
-                }
-            }
-        })
-        .to_output_stream())
-}
-
-#[cfg(test)]
-mod tests {
-    use super::IsEmpty;
-
-    #[test]
-    fn examples_work_as_expected() {
-        use crate::examples::test as test_examples;
-
-        test_examples(IsEmpty {})
-    }
-}

crates/nu-cli/src/commands/keep/command.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
@@ -74,11 +74,12 @@ async fn keep(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStr
 #[cfg(test)]
 mod tests {
     use super::Command;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Command {})
+        Ok(test_examples(Command {})?)
     }
 }

crates/nu-cli/src/commands/keep/until.rs

@@ -3,7 +3,7 @@ use crate::evaluate::evaluate_baseline_expr;
 use crate::prelude::*;
 use log::trace;
 use nu_errors::ShellError;
-use nu_protocol::{hir::ClassifiedCommand, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{hir::ClassifiedCommand, Scope, Signature, SyntaxShape, UntaggedValue, Value};
 
 pub struct SubCommand;
 
@@ -33,7 +33,7 @@ impl WholeStreamCommand for SubCommand {
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
         let registry = Arc::new(registry.clone());
-        let scope = Arc::new(args.call_info.scope.clone());
+        let scope = args.call_info.scope.clone();
 
         let call_info = args.evaluate_once(&registry).await?;
 
@@ -85,19 +85,11 @@ impl WholeStreamCommand for SubCommand {
             .take_while(move |item| {
                 let condition = condition.clone();
                 let registry = registry.clone();
-                let scope = scope.clone();
-                let item = item.clone();
+                let scope = Scope::append_it(scope.clone(), item.clone());
                 trace!("ITEM = {:?}", item);
 
                 async move {
-                    let result = evaluate_baseline_expr(
-                        &*condition,
-                        &registry,
-                        &item,
-                        &scope.vars,
-                        &scope.env,
-                    )
-                    .await;
+                    let result = evaluate_baseline_expr(&*condition, &registry, scope).await;
                     trace!("RESULT = {:?}", result);
 
                     !matches!(result, Ok(ref v) if v.is_true())
@@ -109,12 +101,13 @@ impl WholeStreamCommand for SubCommand {
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }

crates/nu-cli/src/commands/keep/while_.rs

@@ -3,7 +3,7 @@ use crate::evaluate::evaluate_baseline_expr;
 use crate::prelude::*;
 use log::trace;
 use nu_errors::ShellError;
-use nu_protocol::{hir::ClassifiedCommand, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{hir::ClassifiedCommand, Scope, Signature, SyntaxShape, UntaggedValue, Value};
 
 pub struct SubCommand;
 
@@ -33,7 +33,7 @@ impl WholeStreamCommand for SubCommand {
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
         let registry = Arc::new(registry.clone());
-        let scope = Arc::new(args.call_info.scope.clone());
+        let scope = args.call_info.scope.clone();
         let call_info = args.evaluate_once(&registry).await?;
 
         let block = call_info.args.expect_nth(0)?.clone();
@@ -84,20 +84,11 @@ impl WholeStreamCommand for SubCommand {
             .take_while(move |item| {
                 let condition = condition.clone();
                 let registry = registry.clone();
-                let scope = scope.clone();
-                let item = item.clone();
-
+                let scope = Scope::append_it(scope.clone(), item.clone());
                 trace!("ITEM = {:?}", item);
 
                 async move {
-                    let result = evaluate_baseline_expr(
-                        &*condition,
-                        &registry,
-                        &item,
-                        &scope.vars,
-                        &scope.env,
-                    )
-                    .await;
+                    let result = evaluate_baseline_expr(&*condition, &registry, scope).await;
                     trace!("RESULT = {:?}", result);
 
                     matches!(result, Ok(ref v) if v.is_true())
@@ -109,12 +100,13 @@ impl WholeStreamCommand for SubCommand {
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }

crates/nu-cli/src/commands/kill.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape};
@@ -121,11 +121,12 @@ async fn kill(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStr
 #[cfg(test)]
 mod tests {
     use super::Kill;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Kill {})
+        Ok(test_examples(Kill {})?)
     }
 }

crates/nu-cli/src/commands/last.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape, UntaggedValue, Value};
@@ -83,11 +83,12 @@ async fn last(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStr
 #[cfg(test)]
 mod tests {
     use super::Last;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Last {})
+        Ok(test_examples(Last {})?)
     }
 }

crates/nu-cli/src/commands/lines.rs

@@ -75,9 +75,9 @@ async fn lines(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputSt
                 } => {
                     let mut leftover_string = leftover_string.lock();
 
-                    let st = (&*leftover_string).clone() + &st;
-
-                    let mut lines: Vec<String> = st.lines().map(|x| x.to_string()).collect();
+                    let lo_lines = (&*leftover_string).lines().map(|x| x.to_string());
+                    let st_lines = st.lines().map(|x| x.to_string());
+                    let mut lines: Vec<String> = lo_lines.chain(st_lines).collect();
 
                     leftover_string.clear();
 
@@ -125,11 +125,12 @@ async fn lines(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputSt
 #[cfg(test)]
 mod tests {
     use super::Lines;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Lines {})
+        Ok(test_examples(Lines {})?)
     }
 }

crates/nu-cli/src/commands/ls.rs

@@ -89,11 +89,12 @@ impl WholeStreamCommand for Ls {
 #[cfg(test)]
 mod tests {
     use super::Ls;
+    use super::ShellError;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Ls {})
+        Ok(test_examples(Ls {})?)
     }
 }

crates/nu-cli/src/commands/math/avg.rs

@@ -53,7 +53,11 @@ impl WholeStreamCommand for SubCommand {
         vec![Example {
             description: "Get the average of a list of numbers",
             example: "echo [-50 100.0 25] | math avg",
-            result: Some(vec![UntaggedValue::decimal(25).into()]),
+            result: Some(vec![UntaggedValue::decimal_from_float(
+                25.0,
+                Span::unknown(),
+            )
+            .into()]),
         }]
     }
 }
@@ -137,6 +141,28 @@ pub fn average(values: &[Value], name: &Tag) -> Result<Value, ShellError> {
                 )),
             }
         }
+        Value {
+            value: UntaggedValue::Primitive(Primitive::Duration(duration)),
+            ..
+        } => {
+            let left = UntaggedValue::from(Primitive::Duration(duration));
+            let result = nu_data::value::compute_values(Operator::Divide, &left, &total_rows);
+
+            match result {
+                Ok(UntaggedValue::Primitive(Primitive::Duration(result))) => {
+                    Ok(UntaggedValue::duration(result).into_value(name))
+                }
+                Ok(_) => Err(ShellError::labeled_error(
+                    "could not calculate average of non-integer or unrelated types",
+                    "source",
+                    name,
+                )),
+                Err((left_type, right_type)) => Err(ShellError::coerce_error(
+                    left_type.spanned(name.span),
+                    right_type.spanned(name.span),
+                )),
+            }
+        }
         Value {
             value: UntaggedValue::Primitive(other),
             ..
@@ -162,12 +188,13 @@ pub fn average(values: &[Value], name: &Tag) -> Result<Value, ShellError> {
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }

crates/nu-cli/src/commands/math/command.rs

@@ -39,15 +39,15 @@ mod tests {
         sum::summation, utils::calculate, utils::MathFunction, variance::variance,
     };
     use nu_plugin::row;
-    use nu_plugin::test_helpers::value::{decimal, int, table};
+    use nu_plugin::test_helpers::value::{decimal, decimal_from_float, int, table};
     use nu_protocol::Value;
     use std::str::FromStr;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(Command {})
+        Ok(test_examples(Command {})?)
     }
 
     #[test]
@@ -98,17 +98,17 @@ mod tests {
             },
             TestCase {
                 description: "Mixed Values",
-                values: vec![int(10), decimal(26.5), decimal(26.5)],
+                values: vec![int(10), decimal_from_float(26.5), decimal_from_float(26.5)],
                 expected_err: None,
                 expected_res: vec![
                     Ok(decimal(21)),
                     Ok(int(10)),
-                    Ok(decimal(26.5)),
-                    Ok(decimal(26.5)),
-                    Ok(table(&[decimal(26.5)])),
+                    Ok(decimal_from_float(26.5)),
+                    Ok(decimal_from_float(26.5)),
+                    Ok(table(&[decimal_from_float(26.5)])),
                     Ok(decimal(BigDecimal::from_str("7.77817459305202276840928798315333943213319531457321440247173855894902863154158871367713143880202865").expect("Could not convert to decimal from string"))),
                     Ok(decimal(63)),
-                    Ok(decimal(60.5)),
+                    Ok(decimal_from_float(60.5)),
                 ],
             },
             TestCase {
@@ -128,14 +128,14 @@ mod tests {
             },
             TestCase {
                 description: "Mixed Negative Values",
-                values: vec![decimal(-13.5), decimal(-11.5), int(10)],
+                values: vec![decimal_from_float(-13.5), decimal_from_float(-11.5), int(10)],
                 expected_err: None,
                 expected_res: vec![
                     Ok(decimal(-5)),
-                    Ok(decimal(-13.5)),
+                    Ok(decimal_from_float(-13.5)),
                     Ok(int(10)),
-                    Ok(decimal(-11.5)),
-                    Ok(table(&[decimal(-13.5), decimal(-11.5), int(10)])),
+                    Ok(decimal_from_float(-11.5)),
+                    Ok(table(&[decimal_from_float(-13.5), decimal_from_float(-11.5), int(10)])),
                     Ok(decimal(BigDecimal::from_str("10.63798226482196513098036125801342585449179971588207816421068645273754903468375890632981926875247027").expect("Could not convert to decimal from string"))),
                     Ok(decimal(-15)),
                     Ok(decimal(BigDecimal::from_str("113.1666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666667").expect("Could not convert to decimal from string"))),
@@ -151,10 +151,10 @@ mod tests {
                 ],
                 expected_err: None,
                 expected_res: vec![
-                    Ok(row!["col1".to_owned() => decimal(2.5), "col2".to_owned() => decimal(6.5)]),
+                    Ok(row!["col1".to_owned() => decimal_from_float(2.5), "col2".to_owned() => decimal_from_float(6.5)]),
                     Ok(row!["col1".to_owned() => int(1), "col2".to_owned() => int(5)]),
                     Ok(row!["col1".to_owned() => int(4), "col2".to_owned() => int(8)]),
-                    Ok(row!["col1".to_owned() => decimal(2.5), "col2".to_owned() => decimal(6.5)]),
+                    Ok(row!["col1".to_owned() => decimal_from_float(2.5), "col2".to_owned() => decimal_from_float(6.5)]),
                     Ok(row![
                         "col1".to_owned() => table(&[int(1), int(2), int(3), int(4)]),
                         "col2".to_owned() => table(&[int(5), int(6), int(7), int(8)])
@@ -164,7 +164,7 @@ mod tests {
                         "col2".to_owned() => decimal(BigDecimal::from_str("1.118033988749894848204586834365638117720309179805762862135448622705260462818902449707207204189391137").expect("Could not convert to decimal from string"))
                     ]),
                     Ok(row!["col1".to_owned() => int(10), "col2".to_owned() => int(26)]),
-                    Ok(row!["col1".to_owned() => decimal(1.25), "col2".to_owned() => decimal(1.25)]),
+                    Ok(row!["col1".to_owned() => decimal_from_float(1.25), "col2".to_owned() => decimal_from_float(1.25)]),
                 ],
             },
             // TODO-Uncomment once Issue: https://github.com/nushell/nushell/issues/1883 is resolved

crates/nu-cli/src/commands/math/eval.rs

@@ -41,7 +41,11 @@ impl WholeStreamCommand for SubCommand {
         vec![Example {
             description: "Evalulate math in the pipeline",
             example: "echo '10 / 4' | math eval",
-            result: Some(vec![UntaggedValue::decimal(2.5).into()]),
+            result: Some(vec![UntaggedValue::decimal_from_float(
+                2.5,
+                Span::unknown(),
+            )
+            .into()]),
         }]
     }
 }
@@ -96,12 +100,13 @@ pub fn parse<T: Into<Tag>>(math_expression: &str, tag: T) -> Result<Value, Strin
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }

crates/nu-cli/src/commands/math/max.rs

@@ -58,12 +58,13 @@ pub fn maximum(values: &[Value], _name: &Tag) -> Result<Value, ShellError> {
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }

crates/nu-cli/src/commands/math/median.rs

@@ -50,7 +50,11 @@ impl WholeStreamCommand for SubCommand {
         vec![Example {
             description: "Get the median of a list of numbers",
             example: "echo [3 8 9 12 12 15] | math median",
-            result: Some(vec![UntaggedValue::decimal(10.5).into()]),
+            result: Some(vec![UntaggedValue::decimal_from_float(
+                10.5,
+                Span::unknown(),
+            )
+            .into()]),
         }]
     }
 }
@@ -182,12 +186,13 @@ fn compute_average(values: &[Value], name: impl Into<Tag>) -> Result<Value, Shel
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }

crates/nu-cli/src/commands/math/min.rs

@@ -58,12 +58,13 @@ pub fn minimum(values: &[Value], _name: &Tag) -> Result<Value, ShellError> {
 
 #[cfg(test)]
 mod tests {
+    use super::ShellError;
     use super::SubCommand;
 
     #[test]
-    fn examples_work_as_expected() {
+    fn examples_work_as_expected() -> Result<(), ShellError> {
         use crate::examples::test as test_examples;
 
-        test_examples(SubCommand {})
+        Ok(test_examples(SubCommand {})?)
     }
 }