REFACTOR: move the banner from the rust source to the standard library (#8406)

Related to:
- #8311 
- #8353

# Description
with the new `$nu.startup-time` from #8353 and as mentionned in #8311,
we are now able to fully move the `nushell` banner from the `rust`
source base to the standard library.

this PR
- removes all the `rust` source code for the banner
- rewrites a perfect clone of the banner to `std.nu`, called `std
banner`
- call `std banner` from `default_config.nu`

# User-Facing Changes
see the demo: https://asciinema.org/a/566521

- no config will show the banner (e.g. `cargo run --release --
--no-config-file`)
- a custom config without the `if $env.config.show_banner` block and no
call to `std banner` would never show the banner
- a custom config with the block and `config.show_banner = true` will
show the banner
- a custom config with the block and `config.show_banner = false` will
NOT show the banner

# Tests + Formatting
a new test line has been added to `tests.nu` to check the length of the
`std banner` output.
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting
```
$nothing
```

---------

Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

crates/nu-cli/src/repl.rs

@@ -11,13 +11,13 @@ use miette::{IntoDiagnostic, Result};
 use nu_color_config::StyleComputer;
 use nu_command::hook::eval_hook;
 use nu_command::util::get_guaranteed_cwd;
-use nu_engine::{convert_env_values, eval_block};
+use nu_engine::convert_env_values;
-use nu_parser::{lex, parse, trim_quotes_str};
+use nu_parser::{lex, trim_quotes_str};
 use nu_protocol::{
     config::NuCursorShape,
     engine::{EngineState, Stack, StateWorkingSet},
-    format_duration, report_error, report_error_new, HistoryFileFormat, PipelineData, ShellError,
+    report_error, report_error_new, HistoryFileFormat, PipelineData, ShellError, Span, Spanned,
-    Span, Spanned, Value,
+    Value,
 };
 use nu_utils::utils::perf;
 use reedline::{CursorConfig, DefaultHinter, EditCommand, Emacs, SqliteBackedHistory, Vi};
@@ -43,6 +43,7 @@ pub fn evaluate_repl(
     stack: &mut Stack,
     nushell_path: &str,
     prerun_command: Option<Spanned<String>>,
+    load_std_lib: Option<Spanned<String>>,
     entire_start_time: Instant,
 ) -> Result<()> {
     use nu_command::hook;
@@ -153,19 +154,8 @@ pub fn evaluate_repl(
 
     start_time = std::time::Instant::now();
     let sys = sysinfo::System::new();
-
-    let show_banner = config.show_banner;
-    let use_ansi = config.use_ansi_coloring;
-    if show_banner {
-        let banner = get_banner(engine_state, stack);
-        if use_ansi {
-            println!("{banner}");
-        } else {
-            println!("{}", nu_utils::strip_ansi_string_likely(banner));
-        }
-    }
     perf(
-        "get sysinfo/show banner",
+        "get sysinfo",
         start_time,
         file!(),
         line!(),
@@ -185,6 +175,19 @@ pub fn evaluate_repl(
         engine_state.merge_env(stack, get_guaranteed_cwd(engine_state, stack))?;
     }
 
+    engine_state.set_startup_time(entire_start_time.elapsed().as_nanos() as i64);
+
+    if load_std_lib.is_none() && engine_state.get_config().show_banner {
+        eval_source(
+            engine_state,
+            stack,
+            r#"use std banner; banner"#.as_bytes(),
+            "show_banner",
+            PipelineData::empty(),
+            false,
+        );
+    }
+
     loop {
         let loop_start_time = std::time::Instant::now();
 
@@ -445,16 +448,6 @@ pub fn evaluate_repl(
 
         entry_num += 1;
 
-        if entry_num == 1 {
-            engine_state.set_startup_time(entire_start_time.elapsed().as_nanos() as i64);
-            if show_banner {
-                println!(
-                    "Startup Time: {}",
-                    format_duration(engine_state.get_startup_time())
-                );
-            }
-        }
-
         start_time = std::time::Instant::now();
         let input = line_editor.read_line(prompt);
         let shell_integration = config.shell_integration;
@@ -740,104 +733,6 @@ fn map_nucursorshape_to_cursorshape(shape: NuCursorShape) -> SetCursorStyle {
     }
 }
 
-fn get_banner(engine_state: &mut EngineState, stack: &mut Stack) -> String {
-    let age = match eval_string_with_input(
-        engine_state,
-        stack,
-        None,
-        "(date now) - ('2019-05-10 09:59:12-0700' | into datetime)",
-    ) {
-        Ok(Value::Duration { val, .. }) => format_duration(val),
-        _ => "".to_string(),
-    };
-
-    let banner = format!(
-        r#"{}     __  ,
-{} .--()°'.' {}Welcome to {}Nushell{},
-{}'|, . ,'   {}based on the {}nu{} language,
-{} !_-(_\    {}where all data is structured!
-
-Please join our {}Discord{} community at {}https://discord.gg/NtAbbGn{}
-Our {}GitHub{} repository is at {}https://github.com/nushell/nushell{}
-Our {}Documentation{} is located at {}https://nushell.sh{}
-{}Tweet{} us at {}@nu_shell{}
-Learn how to remove this at: {}https://nushell.sh/book/configuration.html#remove-welcome-message{}
-
-It's been this long since {}Nushell{}'s first commit:
-{}{}
-"#,
-        "\x1b[32m",   //start line 1 green
-        "\x1b[32m",   //start line 2
-        "\x1b[0m",    //before welcome
-        "\x1b[32m",   //before nushell
-        "\x1b[0m",    //after nushell
-        "\x1b[32m",   //start line 3
-        "\x1b[0m",    //before based
-        "\x1b[32m",   //before nu
-        "\x1b[0m",    //after nu
-        "\x1b[32m",   //start line 4
-        "\x1b[0m",    //before where
-        "\x1b[35m",   //before Discord purple
-        "\x1b[0m",    //after Discord
-        "\x1b[35m",   //before Discord URL
-        "\x1b[0m",    //after Discord URL
-        "\x1b[1;32m", //before GitHub green_bold
-        "\x1b[0m",    //after GitHub
-        "\x1b[1;32m", //before GitHub URL
-        "\x1b[0m",    //after GitHub URL
-        "\x1b[32m",   //before Documentation
-        "\x1b[0m",    //after Documentation
-        "\x1b[32m",   //before Documentation URL
-        "\x1b[0m",    //after Documentation URL
-        "\x1b[36m",   //before Tweet blue
-        "\x1b[0m",    //after Tweet
-        "\x1b[1;36m", //before @nu_shell cyan_bold
-        "\x1b[0m",    //after @nu_shell
-        "\x1b[32m",   //before Welcome Message
-        "\x1b[0m",    //after Welcome Message
-        "\x1b[32m",   //before Nushell
-        "\x1b[0m",    //after Nushell
-        age,
-        "\x1b[0m", //after banner disable
-    );
-
-    banner
-}
-
-// Taken from Nana's simple_eval
-/// Evaluate a block of Nu code, optionally with input.
-/// For example, source="$in * 2" will multiply the value in input by 2.
-pub fn eval_string_with_input(
-    engine_state: &mut EngineState,
-    stack: &mut Stack,
-    input: Option<Value>,
-    source: &str,
-) -> Result<Value, ShellError> {
-    let (block, delta) = {
-        let mut working_set = StateWorkingSet::new(engine_state);
-        let output = parse(&mut working_set, None, source.as_bytes(), false);
-
-        (output, working_set.render())
-    };
-
-    engine_state.merge_delta(delta)?;
-
-    let input_as_pipeline_data = match input {
-        Some(input) => PipelineData::Value(input, None),
-        None => PipelineData::empty(),
-    };
-
-    eval_block(
-        engine_state,
-        stack,
-        &block,
-        input_as_pipeline_data,
-        false,
-        true,
-    )
-    .map(|x| x.into_value(Span::unknown()))
-}
-
 pub fn get_command_finished_marker(stack: &Stack, engine_state: &EngineState) -> String {
     let exit_code = stack
         .get_env_var(engine_state, "LAST_EXIT_CODE")

crates/nu-std/lib/dt.nu

@@ -0,0 +1,226 @@
+def borrow-year [from: record, current: record] {
+    mut current = $current
+
+    $current.year = $current.year - 1
+    $current.month = $current.month + 12
+
+    $current
+}
+
+def leap-year-days [year] {
+    if $year mod 400 == 0  {
+        29
+    } else if $year mod 4 == 0 and $year mod 100 != 0 {
+        29
+    } else {
+        28
+    }
+}
+
+def borrow-month [from: record, current: record] {
+    mut current = $current
+    if $from.month in [1, 3, 5, 7, 8, 10, 12] {
+        $current.day = $current.day + 31
+        $current.month = $current.month - 1
+        if $current.month < 0 {
+            $current = (borrow-year $from $current)
+        }
+    } else if $from.month in [4, 6, 9, 11] {
+        $current.day = $current.day + 30
+        $current.month = $current.month - 1
+        if $current.month < 0 {
+            $current = (borrow-year $from $current)
+        }
+    } else {
+        # oh February
+        let num_days_feb = (leap-year-days $current.year)
+        $current.day = $current.day + $num_days_feb
+        $current.month = $current.month - 1
+        if $current.month < 0 {
+            $current = (borrow-year $from $current)
+        }
+    }
+
+    $current
+}
+
+def borrow-day [from: record, current: record] {
+    mut current = $current
+    $current.hour = $current.hour + 24
+    $current.day = $current.day - 1
+    if $current.day < 0 {
+        $current = (borrow-month $from $current)
+    }
+
+    $current
+}
+
+def borrow-hour [from: record, current: record] {
+    mut current = $current
+    $current.minute = $current.minute + 60
+    $current.hour = $current.hour - 1
+    if $current.hour < 0 {
+        $current = (borrow-day $from $current)
+    }
+
+    $current
+}
+
+def borrow-minute [from: record, current: record] {
+    mut current = $current
+    $current.second = $current.second + 60
+    $current.minute = $current.minute - 1
+    if $current.minute < 0 {
+        $current = (borrow-hour $from $current)
+    }
+
+    $current
+}
+
+def borrow-second [from: record, current: record] {
+    mut current = $current
+    $current.millisecond = $current.millisecond + 1_000
+    $current.second = $current.second - 1
+    if $current.second < 0 {
+        $current = (borrow-minute $from $current)
+    }
+
+    $current
+}
+
+def borrow-millisecond [from: record, current: record] {
+    mut current = $current
+    $current.microsecond = $current.microsecond + 1_000_000
+    $current.millisecond = $current.millisecond - 1
+    if $current.millisecond < 0 {
+        $current = (borrow-second $from $current)
+    }
+
+    $current
+}
+
+def borrow-microsecond [from: record, current: record] {
+    mut current = $current
+    $current.nanosecond = $current.nanosecond + 1_000_000_000
+    $current.microsecond = $current.microsecond - 1
+    if $current.microsecond < 0 {
+        $current = (borrow-millisecond $from $current)
+    }
+
+    $current
+}
+
+# Subtract two datetimes and return a record with the difference
+# Examples
+# print (datetime-diff 2023-05-07T04:08:45+12:00 2019-05-10T09:59:12+12:00)
+# print (datetime-diff (date now) 2019-05-10T09:59:12-07:00)
+export def datetime-diff [from: datetime, to: datetime] {
+    let from_expanded = ($from | date to-timezone utc | date to-record | merge { millisecond: 0, microsecond: 0})
+    let to_expanded = ($to | date to-timezone utc | date to-record | merge { millisecond: 0, microsecond: 0})
+
+    mut result = { year: ($from_expanded.year - $to_expanded.year), month: ($from_expanded.month - $to_expanded.month)}
+
+    if $result.month < 0 {
+        $result = (borrow-year $from_expanded $result)
+    }
+
+    $result.day = $from_expanded.day - $to_expanded.day
+    if $result.day < 0 {
+        $result = (borrow-month $from_expanded $result)
+    }
+
+    $result.hour = $from_expanded.hour - $to_expanded.hour
+    if $result.hour < 0 {
+        $result = (borrow-day $from_expanded $result)
+    }
+
+    $result.minute = $from_expanded.minute - $to_expanded.minute
+    if $result.minute < 0 {
+        $result = (borrow-hour $from_expanded $result)
+    }
+
+    $result.second = $from_expanded.second - $to_expanded.second
+    if $result.second < 0 {
+        $result = (borrow-minute $from_expanded $result)
+    }
+
+    $result.nanosecond = $from_expanded.nanosecond - $to_expanded.nanosecond
+    if $result.nanosecond < 0 {
+        $result = (borrow-second $from_expanded $result)
+    }
+
+    $result.millisecond = ($result.nanosecond / 1_000_000 | into int) # don't want a decimal
+    $result.microsecond = (($result.nanosecond mod 1_000_000) / 1_000 | into int)
+    $result.nanosecond = ($result.nanosecond mod 1_000 | into int)
+
+    $result
+}
+
+export def pretty-print-duration [dur: duration] {
+    mut result = ""
+    if $dur.year > 0 {
+        if $dur.year > 1 {
+            $result = $"($dur.year)yrs "
+        } else {
+            $result = $"($dur.year)yr "
+        }
+    }
+    if $dur.month > 0 {
+        if $dur.month > 1 {
+            $result = $"($result)($dur.month)months "
+        } else {
+            $result = $"($result)($dur.month)month "
+        }
+    }
+    if $dur.day > 0 {
+        if $dur.day > 1 {
+            $result = $"($result)($dur.day)days "
+        } else {
+            $result = $"($result)($dur.day)day "
+        }
+    }
+    if $dur.hour > 0 {
+        if $dur.hour > 1 {
+            $result = $"($result)($dur.hour)hrs "
+        } else {
+            $result = $"($result)($dur.hour)hr "
+        }
+    }
+    if $dur.minute > 0 {
+        if $dur.minute > 1 {
+            $result = $"($result)($dur.minute)mins "
+        } else {
+            $result = $"($result)($dur.minute)min "
+        }
+    }
+    if $dur.second > 0 {
+        if $dur.second > 1 {
+            $result = $"($result)($dur.second)secs "
+        } else {
+            $result = $"($result)($dur.second)sec "
+        }
+    }
+    if $dur.millisecond > 0 {
+        if $dur.millisecond > 1 {
+            $result = $"($result)($dur.millisecond)ms "
+        } else {
+            $result = $"($result)($dur.millisecond)ms "
+        }
+    }
+    if $dur.microsecond > 0 {
+        if $dur.microsecond > 1 {
+            $result = $"($result)($dur.microsecond)µs "
+        } else {
+            $result = $"($result)($dur.microsecond)µs "
+        }
+    }
+    if $dur.nanosecond > 0 {
+        if $dur.nanosecond > 1 {
+            $result = $"($result)($dur.nanosecond)ns "
+        } else {
+            $result = $"($result)($dur.nanosecond)ns "
+        }
+    }
+
+    $result
+}

crates/nu-std/lib/mod.nu

@@ -9,6 +9,7 @@ export use iter *
 export use log *
 export use testing *
 export use xml *
+export use dt [datetime-diff, pretty-print-duration]
 
 # Add the given paths to the PATH.
 #
@@ -224,3 +225,27 @@ export def bench [
         $report
     }
 }
+
+# print a banner for nushell, with information about the project
+#
+# Example:
+# an example can be found in [this asciinema recording](https://asciinema.org/a/566513)
+export def banner [] {
+let dt = (datetime-diff (date now) 2019-05-10T09:59:12-07:00)
+$"(ansi green)     __  ,(ansi reset)
+(ansi green) .--\(\)°'.' (ansi reset)Welcome to (ansi green)Nushell(ansi reset),
+(ansi green)'|, . ,'   (ansi reset)based on the (ansi green)nu(ansi reset) language,
+(ansi green) !_-\(_\\    (ansi reset)where all data is structured!
+
+Please join our (ansi purple)Discord(ansi reset) community at (ansi purple)https://discord.gg/NtAbbGn(ansi reset)
+Our (ansi green_bold)GitHub(ansi reset) repository is at (ansi green_bold)https://github.com/nushell/nushell(ansi reset)
+Our (ansi green)Documentation(ansi reset) is located at (ansi green)https://nushell.sh(ansi reset)
+(ansi cyan)Tweet(ansi reset) us at (ansi cyan_bold)@nu_shell(ansi reset)
+Learn how to remove this at: (ansi green)https://nushell.sh/book/configuration.html#remove-welcome-message(ansi reset)
+
+It's been this long since (ansi green)Nushell(ansi reset)'s first commit:
+(pretty-print-duration $dt)
+
+Startup Time: ($nu.startup-time)
+"
+}

crates/nu-std/src/lib.rs

@@ -78,6 +78,7 @@ pub fn load_standard_library(
             ("help", include_str!("../lib/help.nu")),
             ("testing", include_str!("../lib/testing.nu")),
             ("xml", include_str!("../lib/xml.nu")),
+            ("dt", include_str!("../lib/dt.nu")),
         ];
 
         // Define commands to be preloaded into the default (top level, unprefixed) namespace.

crates/nu-std/tests/test_std.nu

@@ -22,3 +22,7 @@ export def test_path_add [] {
         assert equal $env.PATH ["fooooo", "foo", "bar", "baz"]
     }
 }
+
+export def test_banner [] {
+    std assert ((std banner | lines | length) == 15)
+}

src/run.rs

@@ -234,6 +234,7 @@ pub(crate) fn run_repl(
         &mut stack,
         config_files::NUSHELL_FOLDER,
         parsed_nu_cli_args.execute,
+        parsed_nu_cli_args.no_std_lib,
         entire_start_time,
     );
     perf(

src/test_bins.rs

@@ -6,6 +6,7 @@ use nu_engine::eval_block;
 use nu_parser::parse;
 use nu_protocol::engine::{EngineState, Stack, StateWorkingSet};
 use nu_protocol::{CliError, PipelineData, Value};
+use nu_std::load_standard_library;
 // use nu_test_support::fs::in_directory;
 
 /// Echo's value of env keys from args
@@ -175,10 +176,12 @@ pub fn nu_repl() {
     let mut engine_state = nu_cli::add_cli_context(create_default_context());
     let mut stack = Stack::new();
 
-    stack.add_env_var("PWD".to_string(), Value::test_string(cwd.to_string_lossy()));
+    engine_state.add_env_var("PWD".into(), Value::test_string(cwd.to_string_lossy()));
 
     let mut last_output = String::new();
 
+    load_standard_library(&mut engine_state).expect("Could not load the standard library.");
+
     for (i, line) in source_lines.iter().enumerate() {
         let cwd = nu_engine::env::current_dir(&engine_state, &stack)
             .unwrap_or_else(|err| outcome_err(&engine_state, &err));