Switch to clap-generated completions

The current completions required a lot of domain-specific knowledge
about each individual shell and their completion functionality. Much of
which is sparsely documented.

While clap does not generate perfect completions, since parameters like
`-e` are missing completions, it does a reasonable job while requiring
no work on writing these completions.

Since access to `cli.rs` isn't possible from the `build.rs`, these
completions aren't always generated on build. Instead a test verifies
that there has been no changes to these completions and provides a
simple code sample for re-generating them. This should provide a simple
solution with minimal overhead.

3 files changed, 308 insertions, 204 deletions

diff --git a/extra/completions/_alacritty b/extra/completions/_alacritty
index 1313128e..32086910 100644
--- a/extra/completions/_alacritty
+++ b/extra/completions/_alacritty
@@ -1,62 +1,135 @@
 #compdef alacritty
 
-# Completions available for the first parameter.
-_alacritty_first_param() {
-    # Main subcommands.
-    _describe "command" "(msg:'Available socket messages')"
+autoload -U is-at-least
 
-    # Default options.
-    _alacritty_main
-}
-
-# Completions available for parameters after the first.
-_alacritty_following_param() {
-    case $words[2] in
-      msg)
-        _alacritty_msg;;
-      *)
-        _alacritty_main;;
-    esac
-}
+_alacritty() {
+    typeset -A opt_args
+    typeset -a _arguments_options
+    local ret=1
 
-# Completions for the main Alacritty executable.
-_alacritty_main() {
-  # Limit some suggestions to the first option.
-  local ignore
-  (( $#words > 2 )) && ignore='!'
+    if is-at-least 5.2; then
+        _arguments_options=(-s -S -C)
+    else
+        _arguments_options=(-s -C)
+    fi
 
-  _arguments \
-    "$ignore(-)"{-h,--help}"[print help information]" \
-    "$ignore(-)"{-V,--version}"[print version information]" \
-    "--print-events[print all events to stdout]" \
-    '(-v)'{-q,-qq}"[reduce the level of verbosity (min is -qq)]" \
-    "--ref-test[generate ref test]" \
-    "--hold[remain open after child process exits]" \
-    '(-q)'{-v,-vv,-vvv}"[increase the level of verbosity (max is -vvv)]" \
-    "--class=[define the window class]:class" \
-    "--embed=[define the X11 window ID (as a decimal integer) to embed Alacritty within]:windowId" \
-    "(-e --command)"{-e,--command}"[execute command (must be last arg)]:program: _command_names -e:*::program arguments: _normal" \
-    "--config-file=[specify an alternative config file]:file:_files" \
-    "*"{-o=,--option=}"[override config file options]:option" \
-    "(-t --title)"{-t=,--title=}"[define the window title]:title" \
-    "--working-directory=[start shell in specified directory]:directory:_directories"\
-    "--socket=[Path for IPC socket creation]:file:_files"
+    local context curcontext="$curcontext" state line
+    _arguments "${_arguments_options[@]}" \
+'-t+[Defines the window title \[default: Alacritty\]]' \
+'--title=[Defines the window title \[default: Alacritty\]]' \
+'--class=[Defines window class/app_id on X11/Wayland \[default: Alacritty\]]' \
+'--embed=[Defines the X11 window ID (as a decimal integer) to embed Alacritty within]' \
+'--working-directory=[Start the shell in the specified working directory]' \
+'--config-file=[Specify alternative configuration file \[default: $XDG_CONFIG_HOME/alacritty/alacritty.yml\]]' \
+'--socket=[Path for IPC socket creation]' \
+'*-e+[Command and args to execute (must be last argument)]' \
+'*--command=[Command and args to execute (must be last argument)]' \
+'*-o+[Override configuration file options \[example: cursor.style=Beam\]]' \
+'*--option=[Override configuration file options \[example: cursor.style=Beam\]]' \
+'--print-events[Print all events to stdout]' \
+'--ref-test[Generates ref test]' \
+'--hold[Remain open after child process exits]' \
+'(-v)*-q[Reduces the level of verbosity (the min level is -qq)]' \
+'(-q)*-v[Increases the level of verbosity (the max level is -vvv)]' \
+'-h[Prints help information]' \
+'--help[Prints help information]' \
+'-V[Prints version information]' \
+'--version[Prints version information]' \
+":: :_alacritty_commands" \
+"*::: :->alacritty" \
+&& ret=0
+    case $state in
+    (alacritty)
+        words=($line[1] "${words[@]}")
+        (( CURRENT += 1 ))
+        curcontext="${curcontext%:*:*}:alacritty-command-$line[1]:"
+        case $line[1] in
+            (msg)
+_arguments "${_arguments_options[@]}" \
+'-s+[IPC socket connection path override]' \
+'--socket=[IPC socket connection path override]' \
+'-h[Prints help information]' \
+'--help[Prints help information]' \
+'-V[Prints version information]' \
+'--version[Prints version information]' \
+":: :_alacritty__msg_commands" \
+"*::: :->msg" \
+&& ret=0
+case $state in
+    (msg)
+        words=($line[1] "${words[@]}")
+        (( CURRENT += 1 ))
+        curcontext="${curcontext%:*:*}:alacritty-msg-command-$line[1]:"
+        case $line[1] in
+            (create-window)
+_arguments "${_arguments_options[@]}" \
+'-h[Prints help information]' \
+'--help[Prints help information]' \
+'-V[Prints version information]' \
+'--version[Prints version information]' \
+&& ret=0
+;;
+(help)
+_arguments "${_arguments_options[@]}" \
+'-h[Prints help information]' \
+'--help[Prints help information]' \
+'-V[Prints version information]' \
+'--version[Prints version information]' \
+&& ret=0
+;;
+        esac
+    ;;
+esac
+;;
+(help)
+_arguments "${_arguments_options[@]}" \
+'-h[Prints help information]' \
+'--help[Prints help information]' \
+'-V[Prints version information]' \
+'--version[Prints version information]' \
+&& ret=0
+;;
+        esac
+    ;;
+esac
 }
 
-# Completions for the `msg` subcommand.
-_alacritty_msg() {
-  # Limit some suggestions to the first option.
-  local ignore
-  (( $#words > 3 )) && ignore='!'
-
-  _arguments \
-    "$ignore(-)"{-h,--help}"[print help information]" \
-    "$ignore(-)"{-V,--version}"[print version information]" \
-    "(-s --socket)"{-s=,--socket=}"[Path for IPC socket creation]:file:_files" \
-    "*: :((create-window:'Create a new window in the same Alacritty process'))"
+(( $+functions[_alacritty_commands] )) ||
+_alacritty_commands() {
+    local commands; commands=(
+        "msg:Available socket messages" \
+"help:Prints this message or the help of the given subcommand(s)" \
+    )
+    _describe -t commands 'alacritty commands' commands "$@"
+}
+(( $+functions[_alacritty__msg__create-window_commands] )) ||
+_alacritty__msg__create-window_commands() {
+    local commands; commands=(
+        
+    )
+    _describe -t commands 'alacritty msg create-window commands' commands "$@"
+}
+(( $+functions[_alacritty__help_commands] )) ||
+_alacritty__help_commands() {
+    local commands; commands=(
+        
+    )
+    _describe -t commands 'alacritty help commands' commands "$@"
+}
+(( $+functions[_alacritty__msg__help_commands] )) ||
+_alacritty__msg__help_commands() {
+    local commands; commands=(
+        
+    )
+    _describe -t commands 'alacritty msg help commands' commands "$@"
+}
+(( $+functions[_alacritty__msg_commands] )) ||
+_alacritty__msg_commands() {
+    local commands; commands=(
+        "create-window:Create a new window in the same Alacritty process" \
+"help:Prints this message or the help of the given subcommand(s)" \
+    )
+    _describe -t commands 'alacritty msg commands' commands "$@"
 }
 
-# Handle arguments based on their position.
-_arguments \
-  "1: :_alacritty_first_param" \
-  "*: :_alacritty_following_param"
+_alacritty "$@"
\ No newline at end of file
diff --git a/extra/completions/alacritty.bash b/extra/completions/alacritty.bash
index 464afe6e..0a9b286e 100644
--- a/extra/completions/alacritty.bash
+++ b/extra/completions/alacritty.bash
@@ -1,55 +1,162 @@
-#/usr/bin/env bash
-
-# Load completion function
-complete -F _alacritty alacritty
-
-# Completion function
-_alacritty()
-{
-    local cur prev prevprev opts
+_alacritty() {
+    local i cur prev opts cmds
     COMPREPLY=()
     cur="${COMP_WORDS[COMP_CWORD]}"
     prev="${COMP_WORDS[COMP_CWORD-1]}"
-    prevprev="${COMP_WORDS[COMP_CWORD-2]}"
-    opts="-h --help -V --version --print-events -q -qq -v -vv -vvv --ref-test --hold -e --command --config-file -o --option -t --title --embed --class --working-directory --socket msg"
+    cmd=""
+    opts=""
 
-    # If `--command` or `-e` is used, stop completing
-    for i in "${!COMP_WORDS[@]}"; do
-        if [[ "${COMP_WORDS[i]}" == "--command" ]] \
-            || [[ "${COMP_WORDS[i]}" == "-e" ]] \
-            && [[ "${#COMP_WORDS[@]}" -gt "$(($i + 2))" ]]
-        then
-            return 0
-        fi
+    for i in ${COMP_WORDS[@]}
+    do
+        case "${i}" in
+            alacritty)
+                cmd="alacritty"
+                ;;
+            
+            create-window)
+                cmd+="__create__window"
+                ;;
+            help)
+                cmd+="__help"
+                ;;
+            msg)
+                cmd+="__msg"
+                ;;
+            *)
+                ;;
+        esac
     done
 
-    # Match the previous word
-    case "${prev}" in
-        --command | -e)
-            # Complete all commands in $PATH
-            COMPREPLY=( $(compgen -c -- "${cur}") )
-            return 0;;
-        --config-file | --socket)
-            # File completion
-            local IFS=$'\n'
-            compopt -o filenames
-            COMPREPLY=( $(compgen -f -- "${cur}") )
-            return 0;;
-        --class | --title | -t)
-            # Don't complete here
-            return 0;;
-        --working-directory)
-            # Directory completion
-            local IFS=$'\n'
-            compopt -o filenames
-            COMPREPLY=( $(compgen -d -- "${cur}") )
-            return 0;;
-        msg)
-            COMPREPLY=( $(compgen -W "-h --help -V --version -s --socket" -- "${cur}") )
-            return 0;;
+    case "${cmd}" in
+        alacritty)
+            opts=" -q -v -h -V -t -e -o  --print-events --ref-test --hold --help --version --title --class --embed --working-directory --config-file --socket --command --option   msg help"
+            if [[ ${cur} == -* || ${COMP_CWORD} -eq 1 ]] ; then
+                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+                return 0
+            fi
+            case "${prev}" in
+                
+                --title)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                    -t)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --class)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --embed)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --working-directory)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --config-file)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --socket)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --command)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                    -e)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                --option)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                    -o)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                *)
+                    COMPREPLY=()
+                    ;;
+            esac
+            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+            return 0
+            ;;
+        
+        alacritty__help)
+            opts=" -h -V  --help --version  "
+            if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
+                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+                return 0
+            fi
+            case "${prev}" in
+                
+                *)
+                    COMPREPLY=()
+                    ;;
+            esac
+            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+            return 0
+            ;;
+        alacritty__msg)
+            opts=" -h -V -s  --help --version --socket   create-window help"
+            if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
+                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+                return 0
+            fi
+            case "${prev}" in
+                
+                --socket)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                    -s)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                *)
+                    COMPREPLY=()
+                    ;;
+            esac
+            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+            return 0
+            ;;
+        alacritty__msg__create__window)
+            opts=" -h -V  --help --version  "
+            if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
+                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+                return 0
+            fi
+            case "${prev}" in
+                
+                *)
+                    COMPREPLY=()
+                    ;;
+            esac
+            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+            return 0
+            ;;
+        alacritty__msg__help)
+            opts=" -h -V  --help --version  "
+            if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
+                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+                return 0
+            fi
+            case "${prev}" in
+                
+                *)
+                    COMPREPLY=()
+                    ;;
+            esac
+            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+            return 0
+            ;;
     esac
-
-    # Show all flags if there was no previous word
-    COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
-    return 0
 }
+
+complete -F _alacritty -o bashdefault -o default alacritty
diff --git a/extra/completions/alacritty.fish b/extra/completions/alacritty.fish
index fa399ffb..48f118c2 100644
--- a/extra/completions/alacritty.fish
+++ b/extra/completions/alacritty.fish
@@ -1,104 +1,28 @@
-# Available subcommands
-set -l commands msg help
-
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -a "msg help"
-
-# Meta
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from help" \
-  -s "v" \
-  -l "version" \
-  -d "Prints version information"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from help" \
-  -s "h" \
-  -l "help" \
-  -d "Prints help information"
-
-# Config
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -f \
-  -l "config-file" \
-  -d "Specify an alternative config file"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "t" \
-  -l "title" \
-  -d "Defines the window title"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -l "class" \
-  -d "Defines the window class"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -l "embed" \
-  -d "Defines the X11 window ID (as a decimal integer) to embed Alacritty within"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -x \
-  -a '(__fish_complete_directories (commandline -ct))' \
-  -l "working-directory" \
-  -d "Start shell in specified directory"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -l "hold" \
-  -d "Remain open after child process exits"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "o" \
-  -l "option" \
-  -d "Override config file options"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -l "socket" \
-  -d "Path for IPC socket creation"
-
-# Output
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -l "print-events" \
-  -d "Print all events to stdout"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "q" \
-  -d "Reduces the level of verbosity (min is -qq)"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "qq" \
-  -d "Reduces the level of verbosity"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "v" \
-  -d "Increases the level of verbosity"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "vv" \
-  -d "Increases the level of verbosity"
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "vvv" \
-  -d "Increases the level of verbosity"
-
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -l "ref-test" \
-  -d "Generates ref test"
-
-complete -c alacritty \
-  -n "not __fish_seen_subcommand_from $commands" \
-  -s "e" \
-  -l "command" \
-  -d "Execute command (must be last arg)"
-
-# Subcommand `msg`
-complete -c alacritty \
-  -n "__fish_seen_subcommand_from msg" \
-  -s "s" \
-  -l "socket" \
-  -d "Socket path override"
-complete -c alacritty \
-  -n "__fish_seen_subcommand_from msg" \
-  -a "create-window help"
+complete -c alacritty -n "__fish_use_subcommand" -s t -l title -d 'Defines the window title [default: Alacritty]'
+complete -c alacritty -n "__fish_use_subcommand" -l class -d 'Defines window class/app_id on X11/Wayland [default: Alacritty]'
+complete -c alacritty -n "__fish_use_subcommand" -l embed -d 'Defines the X11 window ID (as a decimal integer) to embed Alacritty within'
+complete -c alacritty -n "__fish_use_subcommand" -l working-directory -d 'Start the shell in the specified working directory'
+complete -c alacritty -n "__fish_use_subcommand" -l config-file -d 'Specify alternative configuration file [default: $XDG_CONFIG_HOME/alacritty/alacritty.yml]'
+complete -c alacritty -n "__fish_use_subcommand" -l socket -d 'Path for IPC socket creation'
+complete -c alacritty -n "__fish_use_subcommand" -s e -l command -d 'Command and args to execute (must be last argument)'
+complete -c alacritty -n "__fish_use_subcommand" -s o -l option -d 'Override configuration file options [example: cursor.style=Beam]'
+complete -c alacritty -n "__fish_use_subcommand" -l print-events -d 'Print all events to stdout'
+complete -c alacritty -n "__fish_use_subcommand" -l ref-test -d 'Generates ref test'
+complete -c alacritty -n "__fish_use_subcommand" -l hold -d 'Remain open after child process exits'
+complete -c alacritty -n "__fish_use_subcommand" -s q -d 'Reduces the level of verbosity (the min level is -qq)'
+complete -c alacritty -n "__fish_use_subcommand" -s v -d 'Increases the level of verbosity (the max level is -vvv)'
+complete -c alacritty -n "__fish_use_subcommand" -s h -l help -d 'Prints help information'
+complete -c alacritty -n "__fish_use_subcommand" -s V -l version -d 'Prints version information'
+complete -c alacritty -n "__fish_use_subcommand" -f -a "msg" -d 'Available socket messages'
+complete -c alacritty -n "__fish_use_subcommand" -f -a "help" -d 'Prints this message or the help of the given subcommand(s)'
+complete -c alacritty -n "__fish_seen_subcommand_from msg" -s s -l socket -d 'IPC socket connection path override'
+complete -c alacritty -n "__fish_seen_subcommand_from msg" -s h -l help -d 'Prints help information'
+complete -c alacritty -n "__fish_seen_subcommand_from msg" -s V -l version -d 'Prints version information'
+complete -c alacritty -n "__fish_seen_subcommand_from msg" -f -a "create-window" -d 'Create a new window in the same Alacritty process'
+complete -c alacritty -n "__fish_seen_subcommand_from msg" -f -a "help" -d 'Prints this message or the help of the given subcommand(s)'
+complete -c alacritty -n "__fish_seen_subcommand_from create-window" -s h -l help -d 'Prints help information'
+complete -c alacritty -n "__fish_seen_subcommand_from create-window" -s V -l version -d 'Prints version information'
+complete -c alacritty -n "__fish_seen_subcommand_from help" -s h -l help -d 'Prints help information'
+complete -c alacritty -n "__fish_seen_subcommand_from help" -s V -l version -d 'Prints version information'
+complete -c alacritty -n "__fish_seen_subcommand_from help" -s h -l help -d 'Prints help information'
+complete -c alacritty -n "__fish_seen_subcommand_from help" -s V -l version -d 'Prints version information'