kc3-lang/libxkbcommon

diff --git a/meson.build b/meson.build
index 91d0b36..7d5802b 100644
--- a/meson.build
+++ b/meson.build
@@ -417,6 +417,7 @@ man_pages = []
 # Tools
 build_tools = get_option('enable-tools') and cc.has_header_symbol('getopt.h', 'getopt_long', prefix: '#define _GNU_SOURCE')
 if build_tools
+    # Common resources
     libxkbcommon_tools_internal_sources = [
         'tools/tools-common.h',
         'tools/tools-common.c',
@@ -432,10 +433,27 @@ if build_tools
         dependencies: dep_libxkbcommon,
     )
 
+    # Tool: xkbcli
     executable('xkbcli', 'tools/xkbcli.c',
                dependencies: tools_dep, install: true)
     install_man('tools/xkbcli.1')
 
+    if get_option('enable-bash-completion')
+        bash_completion_path = get_option('bash-completion-path')
+        if bash_completion_path == ''
+            bash_completion = dependency('bash-completion', required: false)
+            if bash_completion.found()
+                bash_completion_path = bash_completion.get_variable(pkgconfig: 'completionsdir')
+            else
+                bash_completion_path = get_option('datadir') / 'bash-completion/completions'
+            endif
+        endif
+        install_data('tools/xkbcli-bash-completion.sh',
+                     rename: 'xkbcli',
+                     install_dir: bash_completion_path)
+    endif
+
+    # Tool: compile-keymap
     xkbcli_compile_keymap = executable('xkbcli-compile-keymap',
                                        'tools/compile-keymap.c',
                                        dependencies: tools_dep,
@@ -450,12 +468,16 @@ if build_tools
                c_args: ['-DENABLE_PRIVATE_APIS'],
                include_directories: [include_directories('src', 'include')],
                install: false)
+
+    # Tool: compose
     executable('compose',
                'tools/compose.c',
                dependencies: tools_dep,
                include_directories: [include_directories('src', 'include')],
                install: false)
     configh_data.set10('HAVE_XKBCLI_COMPILE_KEYMAP', true)
+
+    # Tool: how-to-type
     executable('xkbcli-how-to-type',
                'tools/how-to-type.c',
                dependencies: tools_dep,
@@ -463,6 +485,8 @@ if build_tools
                install_dir: dir_libexec)
     install_man('tools/xkbcli-how-to-type.1')
     configh_data.set10('HAVE_XKBCLI_HOW_TO_TYPE', true)
+
+    # Tool: interactive-evdev
     if cc.has_header('linux/input.h')
         executable('xkbcli-interactive-evdev',
                    'tools/interactive-evdev.c',
@@ -481,6 +505,8 @@ if build_tools
                 include_directories: [include_directories('src', 'include')],
                 install: false)
     endif
+
+    # Tool: interactive-x11
     if get_option('enable-x11')
         x11_tools_dep = declare_dependency(
             link_with: libxkbcommon_x11,
@@ -498,6 +524,8 @@ if build_tools
         install_man('tools/xkbcli-interactive-x11.1')
         configh_data.set10('HAVE_XKBCLI_INTERACTIVE_X11', true)
     endif
+
+    # Tool: interactive-wayland
     if get_option('enable-wayland')
         wayland_client_dep = dependency('wayland-client', version: '>=1.2.0', required: false)
         wayland_protocols_dep = dependency('wayland-protocols', version: '>=1.12', required: false)
@@ -534,6 +562,7 @@ You can disable the Wayland xkbcli programs with -Denable-wayland=false.''')
         configh_data.set10('HAVE_XKBCLI_INTERACTIVE_WAYLAND', true)
     endif
 
+    # Tool: list
     if get_option('enable-xkbregistry')
         configh_data.set10('HAVE_XKBCLI_LIST', true)
         executable('xkbcli-list',
@@ -544,6 +573,7 @@ You can disable the Wayland xkbcli programs with -Denable-wayland=false.''')
         install_man('tools/xkbcli-list.1')
     endif
 
+    # Tool: check-messages
     executable('xkb-check-messages',
                'tools/check-messages.c',
                'tools/messages.c',
diff --git a/meson_options.txt b/meson_options.txt
index 924d1f7..d52cc37 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -14,6 +14,11 @@ option(
     description: 'The X locale root [default=$datadir/X11/locale]',
 )
 option(
+    'bash-completion-path',
+    type: 'string',
+    description: 'Directory for bash completion scripts'
+)
+option(
     'default-rules',
     type: 'string',
     value: 'evdev',
@@ -79,3 +84,9 @@ option(
     value: true,
     description: 'Enable building libxkbregistry',
 )
+option(
+    'enable-bash-completion',
+    type: 'boolean',
+    value: true,
+    description: 'Enable installing bash completion scripts',
+)
diff --git a/tools/compile-keymap.c b/tools/compile-keymap.c
index d762624..f49aa3c 100644
--- a/tools/compile-keymap.c
+++ b/tools/compile-keymap.c
@@ -58,6 +58,8 @@ usage(char **argv)
            "Compile the given RMLVO to a keymap and print it\n"
            "\n"
            "Options:\n"
+           " --help\n"
+           "    Print this help and exit\n"
            " --verbose\n"
            "    Enable verbose debugging output\n"
 #if ENABLE_PRIVATE_APIS
diff --git a/tools/xkbcli-bash-completion.sh b/tools/xkbcli-bash-completion.sh
new file mode 100755
index 0000000..fdab116
--- /dev/null
+++ b/tools/xkbcli-bash-completion.sh
@@ -0,0 +1,96 @@
+# bash completion support for xkbcli.
+
+# See completion API documentation: https://github.com/scop/bash-completion
+# NOTE: The script parses the commands help messages to provide the completions,
+#       thus any new subcommand or option will be supported, as long as it has its
+#       entry in the help messages. This should result in low maintenancei effort.
+
+___xkbcli_main()
+{
+    # Initialization: https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L205
+    local cur prev words cword cmd
+    _init_completion -s || return
+
+    # Find subcommand
+    local i=1
+    while [[ "$i" -lt "$COMP_CWORD" ]]; do
+        local s="${COMP_WORDS[i]}"
+        case "$s" in
+            -*) ;;
+            *)
+            cmd="$s"
+            break
+            ;;
+        esac
+        (( i++ ))
+    done
+
+    # Parse available subcommands
+    local line
+    local is_command_list=false
+    local subcommands=()
+    while IFS='' read -r line; do
+        # Traverse subcommand list
+        if [[ "$is_command_list" == true ]]; then
+            # Check for subcommand based on the indentation
+            if [[ "$line" =~ ^[[:blank:]]{2}([[:alpha:]]([[:alnum:]]|-)+)$ ]]; then
+                subcommands+=("${BASH_REMATCH[1]}")
+            # Detect end of subcommand list based on indentation
+            elif [[ "$line" =~ ^[[:graph:]] ]]; then
+                is_command_list=false
+            fi
+        # Detect start of subcommand list
+        elif [[ "$line" == "Commands:" ]]; then
+            is_command_list=true
+        fi
+    # NOTE: <( COMMAND ) Bash construct is “process substitution”.
+    done < <(xkbcli --help)
+
+    # No previous subcommand or incomplete: completion for root xkbcli command
+    if [[ "$i" -eq "$COMP_CWORD" ]]; then
+        local opts
+        # Doc for _parse_help: https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L311
+        opts=$(_parse_help xkbcli)
+        local cur="${COMP_WORDS[COMP_CWORD]}"
+        COMPREPLY=($(compgen -W "${subcommands[*]} $opts" -- "$cur"))
+        return
+    fi
+
+    # Found a supported subcommand: proceed to completion
+    if [[ "${subcommands[*]}" =~ (^| )$cmd( |$) ]]; then
+        ___xkbcli_subcommand "$cmd"
+    fi
+}
+
+___xkbcli_subcommand()
+{
+    # Some special cases
+    case $1 in
+        compile-keymap | interactive-evdev)
+            case ${COMP_WORDS[COMP_CWORD-1]} in
+                --include | --keymap)
+                    _filedir
+                    return;;
+            esac
+            ;;
+        list)
+            if [[ ${COMP_WORDS[COMP_CWORD]} != -* ]]; then
+                _filedir
+                return
+            fi
+            ;;
+    esac
+
+    # Parse help to get command options
+    local opts
+    # Doc for _parse_usage and _parse_help:
+    # • https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L335
+    # • https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L311
+    # We need both as the current help messages adopt both GNU and BSD styles.
+    opts=$(_parse_usage xkbcli "$1 --help")
+    opts+=$(_parse_help xkbcli "$1 --help")
+    local cur="${COMP_WORDS[COMP_CWORD]}"
+    COMPREPLY=($(compgen -W "$opts" -- "$cur"))
+}
+
+complete -F ___xkbcli_main xkbcli
diff --git a/tools/xkbcli.c b/tools/xkbcli.c
index 75f72fe..3602fb9 100644
--- a/tools/xkbcli.c
+++ b/tools/xkbcli.c
@@ -37,6 +37,9 @@ usage(void)
            "Global options:\n"
            "  -h, --help ...... show this help and exit\n"
            "  -V, --version ... show version information and exit\n"
+           /* WARNING: The following is parsed by the bash completion script.
+            *          Any change to the format (in particular to the indentation)
+            *          should kept in the script in sync. */
            "Commands:\n"
 #if HAVE_XKBCLI_LIST
            "  list\n"