Cli.bash_engine: def of cli@0.2.0.0
Import: import cli@0.2.0.0/cli.bend as Cli
Lines 6603-6711 of cli@0.2.0.0/cli.bend: https://jend.leeeet.dev/read.txt?path=cli@0.2.0.0/cli.bend&start_line=6603&end_line=6711

import Base

# The rest of every bash script, for function prefix id and the quoted
# command name: the parser of COMP_WORDS, then the binding.
def bash_engine(+id: String, name: String) -> List<&2, String>:
  [
    "",
    "# Offers each value of kind that starts with $1, written after $2 and cut to",
    "# the part readline completes: the text after the last \"=\" or \":\". Readline",
    "# quotes files and directories; words are quoted here.",
    String.concat([id, "_offer() {"]),
    "  local word full i",
    "  case $kind in",
    "    f) compopt -o filenames; mapfile -t values < <(compgen -f -- \"$1\") ;;",
    "    d) compopt -o filenames; mapfile -t values < <(compgen -d -- \"$1\") ;;",
    "    w)",
    "      for ((i = 0; i < ${#values[@]}; i++)); do",
    "        printf -v 'values[i]' %q \"${values[i]}\"",
    "      done ;;",
    "    *) return ;;",
    "  esac",
    "  for word in \"${values[@]}\"; do",
    "    full=$2$word",
    "    [[ $word == \"$1\"* ]] && COMPREPLY+=(\"${full:${#2}+${#1}-${#tail}}\")",
    "  done",
    "}",
    "",
    String.concat([id, "() {"]),
    "  local -a words=() opts=() subs=() dests=() values=()",
    "  local cur tail word line gap path= want= kind opt many rest i j n=0 end=0 help=0",
    "  COMPREPLY=()",
    "  # Rejoin the \"=\" and \":\" that bash splits words at. COMP_LINE has no blank",
    "  # at such a split, so a \"=\" typed as its own word stays one.",
    "  line=${COMP_LINE#*\"${COMP_WORDS[0]}\"}",
    "  for ((i = 1; i <= COMP_CWORD; i++)); do",
    "    word=${COMP_WORDS[i]}",
    "    tail=${COMP_WORDS[i-1]}",
    "    gap=${line%%[![:blank:]]*}",
    "    line=${line:${#gap}+${#word}}",
    "    if ((i > 1)) && [[ -z $gap ]] &&",
    "      [[ -n $word && -z ${word//[=:]} || -n $tail && -z ${tail//[=:]} ]]; then",
    "      words[${#words[@]}-1]+=$word",
    "    else",
    "      words+=(\"$word\")",
    "    fi",
    "  done",
    "  tail=${COMP_WORDS[COMP_CWORD]}",
    "  [[ -z ${tail//[=:]} ]] && tail=",
    "  cur=${words[${#words[@]}-1]}",
    "  unset 'words[${#words[@]}-1]'",
    String.concat(["  ", id, "_scope"]),
    "  for word in \"${words[@]}\"; do",
    "    if [[ -n $want ]]; then",
    "      want=",
    "    elif ((!end)) && [[ $word == -- ]]; then",
    "      end=1",
    "    elif ((!end)) && [[ $word == --* ]]; then",
    String.concat(["      ", id, "_arg \"${word%%=*}\""]),
    "      [[ -n $kind && $opt == 0 && $word != *=* ]] && want=$word",
    "    elif ((!end)) && [[ $word == -?* ]]; then",
    "      for ((j = 1; j < ${#word}; j++)); do",
    String.concat(["        ", id, "_arg \"-${word:j:1}\""]),
    "        [[ -n $kind ]] || continue",
    "        ((j + 1 == ${#word})) && want=-${word:j:1}",
    "        break",
    "      done",
    "    elif ((${#subs[@]})); then",
    "      ((end)) && return",
    "      if [[ $word == help ]] && ((!help)); then",
    "        help=1",
    "        continue",
    "      fi",
    "      for ((j = 0; j < ${#subs[@]}; j++)); do",
    "        [[ $word == \"${subs[j]}\" ]] && break",
    "      done",
    "      ((j < ${#subs[@]})) || return",
    "      path=${dests[j]}",
    String.concat(["      ", id, "_scope"]),
    "    else",
    "      # n counts the slots filled. The variadic slot stays open, but a rest()",
    "      # value takes every later word, so nothing more completes.",
    "      n=$((n + 1))",
    "      if ((n == many && rest)); then",
    "        end=1",
    "      elif ((n == many)); then",
    "        n=$((n - 1))",
    "      fi",
    "    fi",
    "  done",
    "  if [[ -n $want ]]; then",
    String.concat(["    ", id, "_arg \"$want\""]),
    String.concat(["    ", id, "_offer \"$cur\" ''"]),
    "  elif ((!end)) && [[ $cur == --*=* ]]; then",
    String.concat(["    ", id, "_arg \"${cur%%=*}\""]),
    String.concat(["    ", id, "_offer \"${cur#*=}\" \"${cur%%=*}=\""]),
    "  elif ((!end)) && [[ $cur == -* ]]; then",
    "    values=(\"${opts[@]}\") kind=w",
    "    ((help)) && values=('-h' '--help')",
    String.concat(["    ", id, "_offer \"$cur\" ''"]),
    "  elif ((!end && ${#subs[@]})); then",
    "    values=(\"${subs[@]}\") kind=w",
    "    ((help)) || values+=('help')",
    String.concat(["    ", id, "_offer \"$cur\" ''"]),
    "  elif ((!help)); then",
    String.concat(["    ", id, "_arg $((n + 1))"]),
    String.concat(["    ", id, "_offer \"$cur\" ''"]),
    "  fi",
    "}",
    "",
    String.concat(["complete -F ", id, " ", name]),
  ]

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.concat