Add path separator to char; Update char to engine-p; List all names of all possible chars (#3470)

* Allow querying the current path separator

* Convert char command to engine-p

* Wrap char args into struct

* Add --list option to char command

This lists all the available character names, along with the character
and its unicode points.

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

@@ -1,11 +1,108 @@
 use crate::prelude::*;
 use nu_engine::{FromValue, WholeStreamCommand};
 use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{Signature, SyntaxShape, TaggedDictBuilder, UntaggedValue, Value};
 use nu_source::Tagged;
 
+use indexmap::indexmap;
+use indexmap::map::IndexMap;
+use lazy_static::lazy_static;
+
 pub struct Char;
 
+struct CharArgs {
+    name: Option<Tagged<String>>,
+    rest: Vec<Value>,
+    list: bool,
+    unicode: bool,
+}
+
+lazy_static! {
+    static ref CHAR_MAP: IndexMap<&'static str, String> = indexmap! {
+        // These are some regular characters that either can't used or
+        // it's just easier to use them like this.
+        "newline" => '\n'.to_string(),
+        "enter" => '\n'.to_string(),
+        "nl" => '\n'.to_string(),
+        "tab" => '\t'.to_string(),
+        "sp" => ' '.to_string(),
+        "space" => ' '.to_string(),
+        "pipe" => '|'.to_string(),
+        "left_brace" => '{'.to_string(),
+        "lbrace" => '{'.to_string(),
+        "right_brace" => '}'.to_string(),
+        "rbrace" => '}'.to_string(),
+        "left_paren" => '('.to_string(),
+        "lparen" => '('.to_string(),
+        "right_paren" => ')'.to_string(),
+        "rparen" => ')'.to_string(),
+        "left_bracket" => '['.to_string(),
+        "lbracket" => '['.to_string(),
+        "right_bracket" => ']'.to_string(),
+        "rbracket" => ']'.to_string(),
+        "sep" => std::path::MAIN_SEPARATOR.to_string(),
+        "separator" => std::path::MAIN_SEPARATOR.to_string(),
+
+        // Unicode names came from https://www.compart.com/en/unicode
+        // Private Use Area (U+E000-U+F8FF)
+        // Unicode can't be mixed with Ansi or it will break width calculation
+        "branch" => '\u{e0a0}'.to_string(),                        // 
+        "segment" => '\u{e0b0}'.to_string(),                       // 
+
+        "identical_to" => '\u{2261}'.to_string(),                  // ≡
+        "hamburger" => '\u{2261}'.to_string(),                     // ≡
+        "not_identical_to" => '\u{2262}'.to_string(),              // ≢
+        "branch_untracked" => '\u{2262}'.to_string(),              // ≢
+        "strictly_equivalent_to" => '\u{2263}'.to_string(),        // ≣
+        "branch_identical" => '\u{2263}'.to_string(),              // ≣
+
+        "upwards_arrow" => '\u{2191}'.to_string(),                 // ↑
+        "branch_ahead" => '\u{2191}'.to_string(),                  // ↑
+        "downwards_arrow" => '\u{2193}'.to_string(),               // ↓
+        "branch_behind" => '\u{2193}'.to_string(),                 // ↓
+        "up_down_arrow" => '\u{2195}'.to_string(),                 // ↕
+        "branch_ahead_behind" => '\u{2195}'.to_string(),           // ↕
+
+        "black_right_pointing_triangle" => '\u{25b6}'.to_string(), // ▶
+        "prompt" => '\u{25b6}'.to_string(),                        // ▶
+        "vector_or_cross_product" => '\u{2a2f}'.to_string(),       // ⨯
+        "failed" => '\u{2a2f}'.to_string(),                        // ⨯
+        "high_voltage_sign" => '\u{26a1}'.to_string(),             // ⚡
+        "elevated" => '\u{26a1}'.to_string(),                      // ⚡
+        "tilde" => '~'.to_string(),                                // ~
+        "twiddle" => '~'.to_string(),                              // ~
+        "squiggly" => '~'.to_string(),                             // ~
+        "home" => '~'.to_string(),                                 // ~
+        "hash" => '#'.to_string(),                                 // #
+        "hashtag" => '#'.to_string(),                              // #
+        "pound_sign" => '#'.to_string(),                           // #
+        "sharp" => '#'.to_string(),                                // #
+        "root" => '#'.to_string(),                                 // #
+
+        // Weather symbols
+        "sun" => "☀️".to_string(),
+        "sunny" => "☀️".to_string(),
+        "sunrise" => "☀️".to_string(),
+        "moon" => "🌛".to_string(),
+        "cloudy" => "☁️".to_string(),
+        "cloud" => "☁️".to_string(),
+        "clouds" => "☁️".to_string(),
+        "rainy" => "🌦️".to_string(),
+        "rain" => "🌦️".to_string(),
+        "foggy" => "🌫️".to_string(),
+        "fog" => "🌫️".to_string(),
+        "mist" => '\u{2591}'.to_string(),
+        "haze" => '\u{2591}'.to_string(),
+        "snowy" => "❄️".to_string(),
+        "snow" => "❄️".to_string(),
+        "thunderstorm" => "🌩️".to_string(),
+        "thunder" => "🌩️".to_string(),
+
+        "bel" => '\x07'.to_string(),       // Terminal Bell
+        "backspace" => '\x08'.to_string(), // Backspace
+    };
+}
+
 impl WholeStreamCommand for Char {
     fn name(&self) -> &str {
         "char"
@@ -13,17 +110,18 @@ impl WholeStreamCommand for Char {
 
     fn signature(&self) -> Signature {
         Signature::build("char")
-            .required(
+            .optional(
                 "character",
                 SyntaxShape::Any,
                 "the name of the character to output",
             )
             .rest(SyntaxShape::String, "multiple Unicode bytes")
+            .switch("list", "List all supported character names", Some('l'))
             .switch("unicode", "Unicode string i.e. 1f378", Some('u'))
     }
 
     fn usage(&self) -> &str {
-        "Output special characters (eg. 'newline')."
+        "Output special characters (e.g., 'newline')."
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -57,15 +155,32 @@ impl WholeStreamCommand for Char {
         ]
     }
 
-    fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
+    fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
+        let args_tag = args.call_info.name_tag.clone();
         let args = args.evaluate_once()?;
+        let args = CharArgs {
+            name: args.opt(0)?,
+            rest: args.rest(1)?,
+            list: args.has_flag("list"),
+            unicode: args.has_flag("unicode"),
+        };
 
-        let name: Tagged<String> = args.req(0)?;
+        if args.list {
-        let rest: Vec<Value> = args.rest(1)?;
+            Ok(CHAR_MAP
-        let unicode = args.has_flag("unicode");
+                .iter()
-
+                .map(move |(name, s)| {
-        if unicode {
+                    let mut dict = TaggedDictBuilder::with_capacity(&args_tag, 2);
-            if !rest.is_empty() {
+                    dict.insert_untagged("name", UntaggedValue::string(*name));
+                    dict.insert_untagged("character", UntaggedValue::string(s));
+                    let unicode_parts: Vec<String> =
+                        s.chars().map(|c| format!("{:x}", c as u32)).collect();
+                    dict.insert_untagged("unicode", UntaggedValue::string(unicode_parts.join(" ")));
+                    dict.into_value()
+                })
+                .to_output_stream())
+        } else if let Some(name) = args.name {
+            if args.unicode {
+                if !args.rest.is_empty() {
                     // Setup a new buffer to put all the Unicode bytes in
                     let mut multi_byte = String::new();
                     // Get the first byte
@@ -75,7 +190,7 @@ impl WholeStreamCommand for Char {
                         Err(e) => return Err(e),
                     }
                     // Get the rest of the bytes
-                for byte_part in rest {
+                    for byte_part in args.rest {
                         let byte_part: Tagged<String> = FromValue::from_value(&byte_part)?;
                         let decoded_char = string_to_unicode_char(&byte_part, &byte_part.tag);
                         match decoded_char {
@@ -83,15 +198,15 @@ impl WholeStreamCommand for Char {
                             Err(e) => return Err(e),
                         }
                     }
-                Ok(ActionStream::one(ReturnSuccess::value(
+                    Ok(OutputStream::one(
                         UntaggedValue::string(multi_byte).into_value(name.tag),
-                )))
+                    ))
                 } else {
                     let decoded_char = string_to_unicode_char(&name.item, &name.tag);
                     if let Ok(ch) = decoded_char {
-                    Ok(ActionStream::one(ReturnSuccess::value(
+                        Ok(OutputStream::one(
                             UntaggedValue::string(ch).into_value(name.tag()),
-                    )))
+                        ))
                     } else {
                         Err(ShellError::labeled_error(
                             "error decoding Unicode character",
@@ -103,9 +218,9 @@ impl WholeStreamCommand for Char {
             } else {
                 let special_character = str_to_character(&name.item);
                 if let Some(output) = special_character {
-                Ok(ActionStream::one(ReturnSuccess::value(
+                    Ok(OutputStream::one(
                         UntaggedValue::string(output).into_value(name.tag()),
-                )))
+                    ))
                 } else {
                     Err(ShellError::labeled_error(
                         "error finding named character",
@@ -114,6 +229,13 @@ impl WholeStreamCommand for Char {
                     ))
                 }
             }
+        } else {
+            Err(ShellError::labeled_error(
+                "char requires the name of the character",
+                "missing name of the character",
+                &args_tag,
+            ))
+        }
     }
 }
 
@@ -134,55 +256,7 @@ fn string_to_unicode_char(s: &str, t: &Tag) -> Result<char, ShellError> {
 }
 
 fn str_to_character(s: &str) -> Option<String> {
-    match s {
+    CHAR_MAP.get(s).map(|s| s.into())
-        // These are some regular characters that either can't used or
-        // it's just easier to use them like this.
-        "newline" | "enter" | "nl" => Some("\n".into()),
-        "tab" => Some("\t".into()),
-        "sp" | "space" => Some(" ".into()),
-        "pipe" => Some('|'.to_string()),
-        "left_brace" | "lbrace" => Some('{'.to_string()),
-        "right_brace" | "rbrace" => Some('}'.to_string()),
-        "left_paren" | "lparen" => Some('('.to_string()),
-        "right_paren" | "rparen" => Some(')'.to_string()),
-        "left_bracket" | "lbracket" => Some('['.to_string()),
-        "right_bracket" | "rbracket" => Some(']'.to_string()),
-
-        // Unicode names came from https://www.compart.com/en/unicode
-        // Private Use Area (U+E000-U+F8FF)
-        // Unicode can't be mixed with Ansi or it will break width calculation
-        "branch" => Some('\u{e0a0}'.to_string()),  // 
-        "segment" => Some('\u{e0b0}'.to_string()), // 
-
-        "identical_to" | "hamburger" => Some('\u{2261}'.to_string()), // ≡
-        "not_identical_to" | "branch_untracked" => Some('\u{2262}'.to_string()), // ≢
-        "strictly_equivalent_to" | "branch_identical" => Some('\u{2263}'.to_string()), // ≣
-
-        "upwards_arrow" | "branch_ahead" => Some('\u{2191}'.to_string()), // ↑
-        "downwards_arrow" | "branch_behind" => Some('\u{2193}'.to_string()), // ↓
-        "up_down_arrow" | "branch_ahead_behind" => Some('\u{2195}'.to_string()), // ↕
-
-        "black_right_pointing_triangle" | "prompt" => Some('\u{25b6}'.to_string()), // ▶
-        "vector_or_cross_product" | "failed" => Some('\u{2a2f}'.to_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" | "sunny" | "sunrise" => Some("☀️".to_string()),
-        "moon" => Some("🌛".to_string()),
-        "cloudy" | "cloud" | "clouds" => Some("☁️".to_string()),
-        "rainy" | "rain" => Some("🌦️".to_string()),
-        "foggy" | "fog" => Some("🌫️".to_string()),
-        "mist" | "haze" => Some("\u{2591}".to_string()),
-        "snowy" | "snow" => Some("❄️".to_string()),
-        "thunderstorm" | "thunder" => Some("🌩️".to_string()),
-
-        "bel" => Some('\x07'.to_string()),       // Terminal Bell
-        "backspace" => Some('\x08'.to_string()), // Backspace
-
-        _ => None,
-    }
 }
 
 #[cfg(test)]