dynamic completions filter options

clap_complete/src/dynamic/completer.rs

@@ -3,6 +3,18 @@ use std::ffi::OsString;
 
 use clap_lex::OsStrExt as _;
 
+/// Specifies the number of dashes an argument must already
+/// contain to complete short and long options.
+#[derive(PartialEq, Eq, Clone, Copy, PartialOrd, Ord)]
+pub enum ShowOptions {
+    /// One `-` for short, two `--` for long options.
+    ExactDash,
+    /// At least one `-` to show options.
+    MinOneDash,
+    /// Always complete options.
+    Always,
+}
+
 /// Shell-specific completions
 pub trait Completer {
     /// The recommended file name for the registration code
@@ -31,6 +43,7 @@ pub fn complete(
     args: Vec<std::ffi::OsString>,
     arg_index: usize,
     current_dir: Option<&std::path::Path>,
+    show_options: ShowOptions,
 ) -> Result<Vec<std::ffi::OsString>, std::io::Error> {
     cmd.build();
 
@@ -54,7 +67,14 @@ pub fn complete(
     let mut is_escaped = false;
     while let Some(arg) = raw_args.next(&mut cursor) {
         if cursor == target_cursor {
-            return complete_arg(&arg, current_cmd, current_dir, pos_index, is_escaped);
+            return complete_arg(
+                &arg,
+                current_cmd,
+                current_dir,
+                pos_index,
+                is_escaped,
+                show_options,
+            );
         }
 
         debug!("complete::next: Begin parsing '{:?}'", arg.to_value_os(),);
@@ -90,6 +110,7 @@ fn complete_arg(
     current_dir: Option<&std::path::Path>,
     pos_index: usize,
     is_escaped: bool,
+    show_options: ShowOptions,
 ) -> Result<Vec<std::ffi::OsString>, std::io::Error> {
     debug!(
         "complete_arg: arg={:?}, cmd={:?}, current_dir={:?}, pos_index={}, is_escaped={}",
@@ -123,7 +144,10 @@ fn complete_arg(
                     );
                 }
             }
-        } else if arg.is_escape() || arg.is_stdio() || arg.is_empty() {
+        } else if arg.is_escape()
+            || (show_options >= ShowOptions::MinOneDash && arg.is_stdio())
+            || (show_options == ShowOptions::Always && arg.is_empty())
+        {
             // HACK: Assuming knowledge of is_escape / is_stdio
             completions.extend(
                 crate::generator::utils::longs_and_visible_aliases(cmd)
@@ -132,7 +156,10 @@ fn complete_arg(
             );
         }
 
-        if arg.is_empty() || arg.is_stdio() || arg.is_short() {
+        if arg.is_stdio()
+            || arg.is_short()
+            || (arg.is_empty() && show_options == ShowOptions::Always)
+        {
             let dash_or_arg = if arg.is_empty() {
                 "-".into()
             } else {

clap_complete/src/dynamic/shells/bash.rs

@@ -1,5 +1,7 @@
 use unicode_xid::UnicodeXID as _;
 
+use crate::dynamic::ShowOptions;
+
 /// Bash completions
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct Bash;
@@ -71,7 +73,8 @@ complete -o nospace -o bashdefault -F _clap_complete_NAME BIN
             .ok()
             .and_then(|i| i.parse().ok());
         let ifs: Option<String> = std::env::var("IFS").ok().and_then(|i| i.parse().ok());
-        let completions = crate::dynamic::complete(cmd, args, index, current_dir)?;
+        let completions =
+            crate::dynamic::complete(cmd, args, index, current_dir, ShowOptions::Always)?;
 
         for (i, completion) in completions.iter().enumerate() {
             if i != 0 {

clap_complete/src/dynamic/shells/fish.rs

@@ -0,0 +1,41 @@
+use crate::dynamic::ShowOptions;
+
+/// Fish completions
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct Fish;
+
+impl crate::dynamic::Completer for Fish {
+    fn file_name(&self, name: &str) -> String {
+        format!("{name}.fish")
+    }
+    fn write_registration(
+        &self,
+        _name: &str,
+        bin: &str,
+        completer: &str,
+        buf: &mut dyn std::io::Write,
+    ) -> Result<(), std::io::Error> {
+        let bin = shlex::quote(bin);
+        let completer = shlex::quote(completer);
+        writeln!(
+            buf,
+            r#"complete -x -c {bin} -a "("'{completer}'" complete --shell fish -- (commandline --current-process --tokenize --cut-at-cursor) (commandline --current-token))""#
+        )
+    }
+    fn write_complete(
+        &self,
+        cmd: &mut clap::Command,
+        args: Vec<std::ffi::OsString>,
+        current_dir: Option<&std::path::Path>,
+        buf: &mut dyn std::io::Write,
+    ) -> Result<(), std::io::Error> {
+        let index = args.len() - 1;
+        let completions =
+            crate::dynamic::complete(cmd, args, index, current_dir, ShowOptions::ExactDash)?;
+
+        for completion in completions {
+            writeln!(buf, "{}", completion.to_string_lossy())?;
+        }
+        Ok(())
+    }
+}

clap_complete/src/dynamic/shells/mod.rs

@@ -1,9 +1,11 @@
 //! Shell support
 
 mod bash;
+mod fish;
 mod shell;
 
 pub use bash::*;
+pub use fish::*;
 pub use shell::*;
 
 use std::ffi::OsString;

clap_complete/src/dynamic/shells/shell.rs

@@ -10,6 +10,8 @@ use clap::ValueEnum;
 pub enum Shell {
     /// Bourne Again SHell (bash)
     Bash,
+    /// Friendly Interactive SHell (fish)
+    Fish,
 }
 
 impl Display for Shell {
@@ -37,12 +39,13 @@ impl FromStr for Shell {
 // Hand-rolled so it can work even when `derive` feature is disabled
 impl ValueEnum for Shell {
     fn value_variants<'a>() -> &'a [Self] {
-        &[Shell::Bash]
+        &[Shell::Bash, Shell::Fish]
     }
 
     fn to_possible_value<'a>(&self) -> Option<PossibleValue> {
         Some(match self {
             Shell::Bash => PossibleValue::new("bash"),
+            Shell::Fish => PossibleValue::new("fish"),
         })
     }
 }
@@ -51,6 +54,7 @@ impl Shell {
     fn completer(&self) -> &dyn crate::dynamic::Completer {
         match self {
             Self::Bash => &super::Bash,
+            Self::Fish => &super::Fish,
         }
     }
 }

clap_complete/tests/snapshots/home/dynamic/exhaustive/fish/fish/completions/exhaustive.fish

@@ -0,0 +1 @@
+complete -x -c exhaustive -a "("'exhaustive'" complete --shell fish -- (commandline --current-process --tokenize --cut-at-cursor) (commandline --current-token))"

clap_complete/tests/snapshots/home/dynamic/exhaustive/fish/fish/config.fish

@@ -0,0 +1,7 @@
+set -U fish_greeting ""
+set -U fish_autosuggestion_enabled 0
+function fish_title
+end
+function fish_prompt
+    printf '%% '
+end;

clap_complete/tests/snapshots/home/static/exhaustive/bash/.bashrc

@@ -236,7 +236,7 @@ _exhaustive() {
             fi
             case "${prev}" in
                 --shell)
-                    COMPREPLY=($(compgen -W "bash" -- "${cur}"))
+                    COMPREPLY=($(compgen -W "bash fish" -- "${cur}"))
                     return 0
                     ;;
                 --register)

clap_complete/tests/snapshots/home/static/exhaustive/fish/fish/completions/exhaustive.fish

@@ -104,7 +104,7 @@ complete -c exhaustive -n "__fish_seen_subcommand_from hint" -l email -r -f
 complete -c exhaustive -n "__fish_seen_subcommand_from hint" -l global -d 'everywhere'
 complete -c exhaustive -n "__fish_seen_subcommand_from hint" -s h -l help -d 'Print help'
 complete -c exhaustive -n "__fish_seen_subcommand_from hint" -s V -l version -d 'Print version'
-complete -c exhaustive -n "__fish_seen_subcommand_from complete" -l shell -d 'Specify shell to complete for' -r -f -a "{bash	}"
+complete -c exhaustive -n "__fish_seen_subcommand_from complete" -l shell -d 'Specify shell to complete for' -r -f -a "{bash	,fish	}"
 complete -c exhaustive -n "__fish_seen_subcommand_from complete" -l register -d 'Path to write completion-registration to' -r -F
 complete -c exhaustive -n "__fish_seen_subcommand_from complete" -l global -d 'everywhere'
 complete -c exhaustive -n "__fish_seen_subcommand_from complete" -s h -l help -d 'Print help (see more with \'--help\')'

clap_complete/tests/snapshots/home/static/exhaustive/zsh/zsh/_exhaustive

@@ -309,7 +309,7 @@ _arguments "${_arguments_options[@]}" \
 ;;
 (complete)
 _arguments "${_arguments_options[@]}" \
-'--shell=[Specify shell to complete for]:SHELL:(bash)' \
+'--shell=[Specify shell to complete for]:SHELL:(bash fish)' \
 '--register=[Path to write completion-registration to]:REGISTER:_files' \
 '--global[everywhere]' \
 '-h[Print help (see more with '\''--help'\'')]' \

clap_complete/tests/snapshots/register_dynamic.fish

@@ -0,0 +1 @@
+complete -x -c my-app -a 'my-app'" complete --shell fish -- (commandline --current-process --tokenize --cut-at-cursor) (commandline --current-token)"