tools/xkbcli-bash-completion.sh

   1 # bash completion support for xkbcli.
   2
   3 # See completion API documentation: https://github.com/scop/bash-completion
   4 # NOTE: The script parses the commands help messages to provide the completions,
   5 #       thus any new subcommand or option will be supported, as long as it has its
   6 #       entry in the help messages. This should result in low maintenancei effort.
   7
   8 ___xkbcli_main()
   9 {
  10     # Initialization: https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L205
  11     local cur prev words cword cmd
  12     _init_completion -s || return
  13
  14     # Find subcommand
  15     local i=1
  16     while [[ "$i" -lt "$COMP_CWORD" ]]; do
  17         local s="${COMP_WORDS[i]}"
  18         case "$s" in
  19             -*) ;;
  20             *)
  21             cmd="$s"
  22             break
  23             ;;
  24         esac
  25         (( i++ ))
  26     done
  27
  28     # Parse available subcommands
  29     local line
  30     local is_command_list=false
  31     local subcommands=()
  32     while IFS='' read -r line; do
  33         # Traverse subcommand list
  34         if [[ "$is_command_list" == true ]]; then
  35             # Check for subcommand based on the indentation
  36             if [[ "$line" =~ ^[[:blank:]]{2}([[:alpha:]]([[:alnum:]]|-)+)$ ]]; then
  37                 subcommands+=("${BASH_REMATCH[1]}")
  38             # Detect end of subcommand list based on indentation
  39             elif [[ "$line" =~ ^[[:graph:]] ]]; then
  40                 is_command_list=false
  41             fi
  42         # Detect start of subcommand list
  43         elif [[ "$line" == "Commands:" ]]; then
  44             is_command_list=true
  45         fi
  46     # NOTE: <( COMMAND ) Bash construct is “process substitution”.
  47     done < <(xkbcli --help)
  48
  49     # No previous subcommand or incomplete: completion for root xkbcli command
  50     if [[ "$i" -eq "$COMP_CWORD" ]]; then
  51         local opts
  52         # Doc for _parse_help: https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L311
  53         opts=$(_parse_help xkbcli)
  54         local cur="${COMP_WORDS[COMP_CWORD]}"
  55         COMPREPLY=($(compgen -W "${subcommands[*]} $opts" -- "$cur"))
  56         return
  57     fi
  58
  59     # Found a supported subcommand: proceed to completion
  60     if [[ "${subcommands[*]}" =~ (^| )$cmd( |$) ]]; then
  61         ___xkbcli_subcommand "$cmd"
  62     fi
  63 }
  64
  65 ___xkbcli_subcommand()
  66 {
  67     # Some special cases
  68     case $1 in
  69         compile-keymap | interactive-evdev)
  70             case ${COMP_WORDS[COMP_CWORD-1]} in
  71                 --include | --keymap)
  72                     _filedir
  73                     return;;
  74             esac
  75             ;;
  76         list)
  77             if [[ ${COMP_WORDS[COMP_CWORD]} != -* ]]; then
  78                 _filedir
  79                 return
  80             fi
  81             ;;
  82     esac
  83
  84     # Parse help to get command options
  85     local opts
  86     # Doc for _parse_usage and _parse_help:
  87     # • https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L335
  88     # • https://github.com/scop/bash-completion/blob/fdf4456186eb4548ef628e65fb1be73d8e4695e9/bash_completion.d/000_bash_completion_compat.bash#L311
  89     # We need both as the current help messages adopt both GNU and BSD styles.
  90     opts=$(_parse_usage xkbcli "$1 --help")
  91     opts+=$(_parse_help xkbcli "$1 --help")
  92     local cur="${COMP_WORDS[COMP_CWORD]}"
  93     COMPREPLY=($(compgen -W "$opts" -- "$cur"))
  94 }
  95
  96 complete -F ___xkbcli_main xkbcli