zsh/Completion/Base/Widget/_complete_help

#compdef -k complete-word \C-xh

_complete_help() {
  eval "$_comp_setup"

  local _sort_tags=_help_sort_tags text i j k tmp
  typeset -A help_funcs help_tags help_sfuncs help_styles

  compadd() { return 1 }
  zstyle() {
    local _f="${${(@)${(@)funcstack[2,(i)_(main_complete|complete|approximate|normal)]}:#_(dispatch|wanted|requested|all_labels|next_label)}% *}"

    [[ -z "$_f" ]] && _f="${${(@)funcstack[2,(i)_(main_complete|complete|approximate|normal)]}:#_(dispatch|wanted|requested|all_labels|next_label)}"

    if [[ "$help_sfuncs[$2]" != *${_f}* ||
          "$help_styles[${2}${_f}]" != *${3}* ]]; then

      [[ "$help_sfuncs[$2]" != *${_f}* ]] && help_sfuncs[$2]+=$'\0'"${_f}"
      local _t

      case "$1" in
      -s) _t='[string] ';;
      -a) _t='[array]  ';;
      -h) _t='[assoc]  ';;
      *)  _t='[boolean]';;
      esac
      help_styles[${2}${_f}]+=",${_t} ${3}:${_f}"
    fi

    # No need to call the completers more than once with different match specs.

    if [[ "$3" = matcher-list ]]; then
      set -A "$4" ''
    else
      builtin zstyle "$@"
    fi
  }
  trap 'unfunction compadd zstyle' EXIT INT

  _main_complete

  unfunction compadd zstyle
  trap - EXIT INT

  for i in "${(@ok)help_funcs}"; do
    text+=$'\n'"tags in context :completion:${i}:"
    tmp=()
    for j in "${(@ps.\0.)help_funcs[$i][2,-1]}"; do
      tmp+=( "${(@s.,.)help_tags[${i}${j}][2,-1]}" )
    done
    zformat -a tmp '  (' "$tmp[@]"
    tmp=( $'\n    '${^tmp}')' )
    text+="${tmp}"
  done

  if [[ ${NUMERIC:-1} -ne 1 ]]; then
    text+=$'\n'
    for i in "${(@ok)help_sfuncs}"; do
      text+=$'\n'"styles in context ${i}"
      tmp=()
      for j in "${(@ps.\0.)help_sfuncs[$i][2,-1]}"; do
        tmp+=( "${(@s.,.)help_styles[${i}${j}][2,-1]}" )
      done
      zformat -a tmp '  (' "$tmp[@]"
      tmp=( $'\n    '${^tmp}')' )
      text+="${tmp}"
    done
  fi
  compstate[list]='list force'
  compstate[insert]=''

  compadd -UX "$text[2,-1]" -n ''
}

_help_sort_tags() {
  local f="${${(@)${(@)funcstack[3,(i)_(main_complete|complete|approximate|normal)]}:#_(dispatch|wanted|requested|all_labels|next_label)}% *}"

  if [[ "$help_funcs[$curcontext]" != *${f}* ||
        "$help_tags[${curcontext}${f}]" != *(${(j:|:)~argv})* ]]; then
    [[ "$help_funcs[$curcontext]" != *${f}* ]] &&
        help_funcs[$curcontext]+=$'\0'"${f}"
    help_tags[${curcontext}${f}]+=",${argv}:${f}"
    comptry "$@"
  fi
}

_complete_help "$@"