#autoload

local tags def expl descr action mesgs nm="$compstate[nmatches]" subopts
local opt curcontext="$curcontext"

subopts=()
while getopts 'O:C:' opt; do
  case "$opt" in
  O) subopts=( "${(@P)OPTARG}" ) ;;
  C) curcontext="${curcontext%:*}:$OPTARG" ;;
  esac
done

shift OPTIND-1

[[ "$1" = -(|-) ]] && shift

mesgs=()

_tags "${(@)argv%%:*}"

while _tags; do
  for def; do
    if _requested "${def%%:*}"; then
      descr="${${def#*:}%%:*}"
      action="${def#*:*:}"

      _description "${def%%:*}" expl "$descr"

      if [[ "$action" = \ # ]]; then

        # An empty action means that we should just display a message.

        mesgs=( "$mesgs[@]" "$descr")
      elif [[ "$action" = \(\(*\)\) ]]; then
        local ws

        # ((...)) contains literal strings with descriptions.

        eval ws\=\( "${action[3,-3]}" \)

        _describe "$descr" ws -M 'r:|[_-]=* r:|=*' "$subopts[@]"
      elif [[ "$action" = \(*\) ]]; then

        # Anything inside `(...)' is added directly.

        _loop "${def%%:*}" expl "$descr" \
            compadd "$subopts[@]" - ${=action[2,-2]}
      elif [[ "$action" = \{*\} ]]; then

        # A string in braces is evaluated.

        while _try "${def%%:*}" expl "$descr"; do
          eval "$action[2,-2]"
        done
      elif [[ "$action" = \ * ]]; then

        # If the action starts with a space, we just call it.

        eval "action=( $action )"
        while _try "${def%%:*}" expl "$descr"; do
          "$action[@]"
        done
      else

        # Otherwise we call it with the description-arguments built above.

        eval "action=( $action )"
        _loop "${def%%:*}" expl "$descr" \
            "$action[1]" "$subopts[@]" "${(@)action[2,-1]}"
      fi
    fi
  done
  [[ nm -ne compstate[nmatches] ]] && return 0
done

for descr in "$mesgs[@]"; do
  _message "$descr"
done

return 1