External it and nu variable column path fetch support. (#1379)

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

@@ -14,6 +14,18 @@ impl ExternalArg {
     pub fn is_it(&self) -> bool {
         self.has("$it")
     }
+
+    pub fn is_nu(&self) -> bool {
+        self.has("$nu")
+    }
+
+    pub fn looks_like_it(&self) -> bool {
+        self.arg.starts_with("$it") && (self.arg.starts_with("$it.") || self.is_it())
+    }
+
+    pub fn looks_like_nu(&self) -> bool {
+        self.arg.starts_with("$nu") && (self.arg.starts_with("$nu.") || self.is_nu())
+    }
 }
 
 impl std::ops::Deref for ExternalArg {
@@ -54,7 +66,11 @@ pub struct ExternalCommand {
 
 impl ExternalCommand {
     pub fn has_it_argument(&self) -> bool {
-        self.args.iter().any(|arg| arg.has("$it"))
+        self.args.iter().any(|arg| arg.looks_like_it())
+    }
+
+    pub fn has_nu_argument(&self) -> bool {
+        self.args.iter().any(|arg| arg.looks_like_nu())
     }
 }
 

src/commands/classified/external.rs

@@ -3,8 +3,11 @@ use futures::stream::StreamExt;
 use futures_codec::{FramedRead, LinesCodec};
 use log::trace;
 use nu_errors::ShellError;
+use nu_parser::commands::classified::external::ExternalArg;
 use nu_parser::ExternalCommand;
-use nu_protocol::{Primitive, ShellTypeName, UntaggedValue, Value};
+use nu_protocol::{ColumnPath, Primitive, ShellTypeName, UntaggedValue, Value};
+use nu_source::{Tag, Tagged};
+use nu_value_ext::as_column_path;
 use std::io::Write;
 use std::ops::Deref;
 use std::process::{Command, Stdio};
@@ -16,7 +19,7 @@ pub fn nu_value_to_string(command: &ExternalCommand, from: &Value) -> Result<Str
         | UntaggedValue::Primitive(Primitive::Line(s)) => Ok(s.clone()),
         UntaggedValue::Primitive(Primitive::Path(p)) => Ok(p.to_string_lossy().to_string()),
         unsupported => Err(ShellError::labeled_error(
-            format!("$it needs string data (given: {})", unsupported.type_name()),
+            format!("needs string data (given: {})", unsupported.type_name()),
             "expected a string",
             &command.name_tag,
         )),
@@ -58,13 +61,59 @@ pub(crate) async fn run_external_command(
         ));
     }
 
-    if command.has_it_argument() {
+    if command.has_it_argument() || command.has_nu_argument() {
         run_with_iterator_arg(command, context, input, is_last).await
     } else {
         run_with_stdin(command, context, input, is_last).await
     }
 }
 
+fn prepare_column_path_for_fetching_it_variable(
+    argument: &ExternalArg,
+) -> Result<Tagged<ColumnPath>, ShellError> {
+    // We have "$it.[contents of interest]"
+    // and start slicing from "$it.[member+]"
+    //                             ^ here.
+    let key = nu_source::Text::from(argument.deref()).slice(4..argument.len());
+
+    to_column_path(&key, &argument.tag)
+}
+
+fn prepare_column_path_for_fetching_nu_variable(
+    argument: &ExternalArg,
+) -> Result<Tagged<ColumnPath>, ShellError> {
+    // We have "$nu.[contents of interest]"
+    // and start slicing from "$nu.[member+]"
+    //                             ^ here.
+    let key = nu_source::Text::from(argument.deref()).slice(4..argument.len());
+
+    to_column_path(&key, &argument.tag)
+}
+
+fn to_column_path(
+    path_members: &str,
+    tag: impl Into<Tag>,
+) -> Result<Tagged<ColumnPath>, ShellError> {
+    let tag = tag.into();
+
+    as_column_path(
+        &UntaggedValue::Table(
+            path_members
+                .split('.')
+                .map(|x| {
+                    let member = match x.parse::<u64>() {
+                        Ok(v) => UntaggedValue::int(v),
+                        Err(_) => UntaggedValue::string(x),
+                    };
+
+                    member.into_value(&tag)
+                })
+                .collect(),
+        )
+        .into_value(&tag),
+    )
+}
+
 async fn run_with_iterator_arg(
     command: ExternalCommand,
     context: &mut Context,
@@ -87,14 +136,136 @@ async fn run_with_iterator_arg(
             let path = &path;
             let args = command.args.clone();
 
-            let it_replacement = match nu_value_to_string(&command, &value) {
-                Ok(value) => value,
-                Err(reason) => {
-                    yield Ok(Value {
-                        value: UntaggedValue::Error(reason),
-                        tag: name_tag
-                    });
-                    return;
+            let it_replacement = {
+                if command.has_it_argument() {
+                    let empty_arg = ExternalArg {
+                        arg: "".to_string(),
+                        tag: name_tag.clone()
+                    };
+
+                    let key = args.iter()
+                        .find(|arg| arg.looks_like_it())
+                        .unwrap_or_else(|| &empty_arg);
+
+                    if args.iter().all(|arg| !arg.is_it()) {
+                        let key = match prepare_column_path_for_fetching_it_variable(&key) {
+                            Ok(keypath) => keypath,
+                            Err(reason) => {
+                                yield Ok(Value {
+                                    value: UntaggedValue::Error(reason),
+                                    tag: name_tag
+                                });
+                                return;
+                            }
+                        };
+
+                        match crate::commands::get::get_column_path(&key, &value) {
+                            Ok(field) => {
+                                match nu_value_to_string(&command, &field) {
+                                    Ok(val) => Some(val),
+                                    Err(reason) => {
+                                        yield Ok(Value {
+                                            value: UntaggedValue::Error(reason),
+                                            tag: name_tag
+                                        });
+                                        return;
+                                    },
+                                }
+                            },
+                            Err(reason) => {
+                                yield Ok(Value {
+                                    value: UntaggedValue::Error(reason),
+                                    tag: name_tag
+                                });
+                                return;
+                            }
+                        }
+                    } else {
+                        match nu_value_to_string(&command, &value) {
+                            Ok(val) => Some(val),
+                            Err(reason) => {
+                                yield Ok(Value {
+                                    value: UntaggedValue::Error(reason),
+                                    tag: name_tag
+                                });
+                                return;
+                            },
+                        }
+                    }
+                } else {
+                    None
+                }
+            };
+
+            let nu_replacement = {
+                if command.has_nu_argument() {
+                    let empty_arg = ExternalArg {
+                        arg: "".to_string(),
+                        tag: name_tag.clone()
+                    };
+
+                    let key = args.iter()
+                        .find(|arg| arg.looks_like_nu())
+                        .unwrap_or_else(|| &empty_arg);
+
+                    let nu_var = match crate::evaluate::variables::nu(&name_tag) {
+                        Ok(variables) => variables,
+                        Err(reason) => {
+                            yield Ok(Value {
+                                value: UntaggedValue::Error(reason),
+                                tag: name_tag
+                            });
+                            return;
+                        }
+                    };
+
+                    if args.iter().all(|arg| !arg.is_nu()) {
+                        let key = match prepare_column_path_for_fetching_nu_variable(&key) {
+                            Ok(keypath) => keypath,
+                            Err(reason) => {
+                                yield Ok(Value {
+                                    value: UntaggedValue::Error(reason),
+                                    tag: name_tag
+                                });
+                                return;
+                            }
+                        };
+
+                        match crate::commands::get::get_column_path(&key, &nu_var) {
+                            Ok(field) => {
+                                match nu_value_to_string(&command, &field) {
+                                    Ok(val) => Some(val),
+                                    Err(reason) => {
+                                        yield Ok(Value {
+                                            value: UntaggedValue::Error(reason),
+                                            tag: name_tag
+                                        });
+                                        return;
+                                    },
+                                }
+                            },
+                            Err(reason) => {
+                                yield Ok(Value {
+                                    value: UntaggedValue::Error(reason),
+                                    tag: name_tag
+                                });
+                                return;
+                            }
+                        }
+                    } else {
+                        match nu_value_to_string(&command, &nu_var) {
+                            Ok(val) => Some(val),
+                            Err(reason) => {
+                                yield Ok(Value {
+                                    value: UntaggedValue::Error(reason),
+                                    tag: name_tag
+                                });
+                                return;
+                            },
+                        }
+                    }
+                } else {
+                    None
                 }
             };
 
@@ -102,25 +273,44 @@ async fn run_with_iterator_arg(
                 if arg.chars().all(|c| c.is_whitespace()) {
                     None
                 } else {
-                    let arg = if arg.is_it() {
-                        let value = it_replacement.to_owned();
-                        let mut value = expand_tilde(&value, || home_dir.as_ref()).as_ref().to_string();
-                        #[cfg(not(windows))]
-                        {
-                            value = {
-                                if argument_contains_whitespace(&value) && !argument_is_quoted(&value) {
-                                    add_quotes(&value)
-                                } else {
-                                    value
-                                }
-                            };
+                    let arg = if arg.looks_like_it() {
+                        if let Some(mut value) = it_replacement.to_owned() {
+                            let mut value = expand_tilde(&value, || home_dir.as_ref()).as_ref().to_string();
+                            #[cfg(not(windows))]
+                            {
+                                value = {
+                                    if argument_contains_whitespace(&value) && !argument_is_quoted(&value) {
+                                        add_quotes(&value)
+                                    } else {
+                                        value
+                                    }
+                                };
+                            }
+                            Some(value)
+                        } else {
+                            None
+                        }
+                    } else if arg.looks_like_nu() {
+                        if let Some(mut value) = nu_replacement.to_owned() {
+                            #[cfg(not(windows))]
+                            {
+                                value = {
+                                    if argument_contains_whitespace(&value) && !argument_is_quoted(&value) {
+                                        add_quotes(&value)
+                                    } else {
+                                        value
+                                    }
+                                };
+                            }
+                            Some(value)
+                        } else {
+                            None
                         }
-                        value
                     } else {
-                        arg.to_string()
+                        Some(arg.to_string())
                     };
 
-                    Some(arg)
+                    arg
                 }
             }).collect::<Vec<String>>();
 

src/evaluate/evaluator.rs

@@ -6,8 +6,8 @@ use log::trace;
 use nu_errors::{ArgumentError, ShellError};
 use nu_parser::hir::{self, Expression, SpannedExpression};
 use nu_protocol::{
-    ColumnPath, Evaluate, Primitive, RangeInclusion, Scope, TaggedDictBuilder, UnspannedPathMember,
-    UntaggedValue, Value,
+    ColumnPath, Evaluate, Primitive, RangeInclusion, Scope, UnspannedPathMember, UntaggedValue,
+    Value,
 };
 use nu_source::Text;
 
@@ -158,31 +158,7 @@ fn evaluate_reference(
     match name {
         hir::Variable::It(_) => Ok(scope.it.value.clone().into_value(tag)),
         hir::Variable::Other(inner) => match inner.slice(source) {
-            x if x == "nu" => {
-                let mut nu_dict = TaggedDictBuilder::new(&tag);
-
-                let mut dict = TaggedDictBuilder::new(&tag);
-                for v in std::env::vars() {
-                    if v.0 != "PATH" && v.0 != "Path" {
-                        dict.insert_untagged(v.0, UntaggedValue::string(v.1));
-                    }
-                }
-                nu_dict.insert_value("env", dict.into_value());
-
-                let config = crate::data::config::read(&tag, &None)?;
-                nu_dict.insert_value("config", UntaggedValue::row(config).into_value(&tag));
-
-                let mut table = vec![];
-                let path = std::env::var_os("PATH");
-                if let Some(paths) = path {
-                    for path in std::env::split_paths(&paths) {
-                        table.push(UntaggedValue::path(path).into_value(&tag));
-                    }
-                }
-                nu_dict.insert_value("path", UntaggedValue::table(&table).into_value(&tag));
-
-                Ok(nu_dict.into_value())
-            }
+            x if x == "nu" => crate::evaluate::variables::nu(tag),
             x => Ok(scope
                 .vars
                 .get(x)

src/evaluate/mod.rs

@@ -1,5 +1,6 @@
 pub(crate) mod evaluate_args;
 pub(crate) mod evaluator;
 pub(crate) mod operator;
+pub(crate) mod variables;
 
 pub(crate) use evaluator::evaluate_baseline_expr;

src/evaluate/variables.rs

@@ -0,0 +1,31 @@
+use nu_errors::ShellError;
+use nu_protocol::{TaggedDictBuilder, UntaggedValue, Value};
+use nu_source::Tag;
+
+pub fn nu(tag: impl Into<Tag>) -> Result<Value, ShellError> {
+    let tag = tag.into();
+
+    let mut nu_dict = TaggedDictBuilder::new(&tag);
+
+    let mut dict = TaggedDictBuilder::new(&tag);
+    for v in std::env::vars() {
+        if v.0 != "PATH" && v.0 != "Path" {
+            dict.insert_untagged(v.0, UntaggedValue::string(v.1));
+        }
+    }
+    nu_dict.insert_value("env", dict.into_value());
+
+    let config = crate::data::config::read(&tag, &None)?;
+    nu_dict.insert_value("config", UntaggedValue::row(config).into_value(&tag));
+
+    let mut table = vec![];
+    let path = std::env::var_os("PATH");
+    if let Some(paths) = path {
+        for path in std::env::split_paths(&paths) {
+            table.push(UntaggedValue::path(path).into_value(&tag));
+        }
+    }
+    nu_dict.insert_value("path", UntaggedValue::table(&table).into_value(&tag));
+
+    Ok(nu_dict.into_value())
+}

tests/shell/pipeline/commands/external.rs

@@ -22,7 +22,7 @@ fn shows_error_for_command_not_found() {
 
 mod it_evaluation {
     use super::nu;
-    use nu_test_support::fs::Stub::{EmptyFile, FileWithContentToBeTrimmed};
+    use nu_test_support::fs::Stub::{EmptyFile, FileWithContent, FileWithContentToBeTrimmed};
     use nu_test_support::{pipeline, playground::Playground};
 
     #[test]
@@ -76,6 +76,29 @@ mod it_evaluation {
             assert_eq!(actual, "AndrásWithKitKat");
         })
     }
+
+    #[test]
+    fn supports_fetching_given_a_column_path_to_it() {
+        Playground::setup("it_argument_test_3", |dirs, sandbox| {
+            sandbox.with_files(vec![FileWithContent(
+                "sample.toml",
+                r#"
+                    nu_party_venue = "zion"
+                "#,
+            )]);
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    open sample.toml
+                    | cococo $it.nu_party_venue
+                    | echo $it
+                "#
+            ));
+
+            assert_eq!(actual, "zion");
+        })
+    }
 }
 
 mod stdin_evaluation {