basic nushell completions

complete/src/lib.rs

@@ -16,6 +16,7 @@
 mod fish;
 mod man;
 mod md;
+mod nu;
 mod zsh;
 
 /// A description of a CLI command
@@ -72,6 +73,7 @@ pub fn render(c: &Command, shell: &str) -> String {
         "md" => md::render(c),
         "fish" => fish::render(c),
         "zsh" => zsh::render(c),
+        "nu" | "nushell" => nu::render(c),
         "man" => man::render(c),
         "sh" | "bash" | "csh" | "elvish" | "powershell" => panic!("shell '{shell}' completion is not implemented yet!"),
         _ => panic!("unknown option '{shell}'! Expected one of: \"md\", \"fish\", \"zsh\", \"man\", \"sh\", \"bash\", \"csh\", \"elvish\", \"powershell\""),

complete/src/nu.rs

@@ -0,0 +1,51 @@
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+use crate::{Arg, Command, Flag, Value};
+use std::fmt::Write;
+
+/// Create completion script for `nushell`
+pub fn render(c: &Command) -> String {
+    let mut args = Vec::new();
+    let indent = " ".repeat(4);
+
+    for Arg {
+        short,
+        long,
+        help,
+        value: _value,
+    } in &c.args
+    {
+        for Flag { flag, value } in short {
+            let value = if let Value::Required(_) | Value::Optional(_) = value {
+                ": string"
+            } else {
+                ""
+            };
+            args.push((format!("-{flag}{value}"), help));
+        }
+        for Flag { flag, value } in long {
+            let value = if let Value::Required(_) | Value::Optional(_) = value {
+                ": string"
+            } else {
+                ""
+            };
+            args.push((format!("--{flag}{value}"), help));
+        }
+    }
+    let longest_arg = args.iter().map(|a| a.0.len()).max().unwrap_or_default();
+    let mut arg_str = String::new();
+    for (a, h) in args {
+        writeln!(arg_str, "{indent}{a:<longest_arg$} # {h}").unwrap();
+    }
+    template(c.name, &arg_str)
+}
+
+fn template(name: &str, args: &str) -> String {
+    format!(
+        "\
+        export extern {name} [\n{args}\
+        ]\n\
+        "
+    )
+}