zsh capistrano completeion function

_capistrano.zsh

#compdef cap
#autoload

# From zsh-users (https://github.com/zsh-users/zsh-completions)
# Mix with oh-my-zsh pull request #367 (https://github.com/robbyrussell/oh-my-zsh/pull/367)
_cap() {
  local curcontext="$curcontext" state line cmds ret=1
  local cache_file='tmp/.cap_tasks~'

  # TODO use zsh built-in cache instead of cache_file
  # zstyle -s ":completion:${curcontext}:" cache-policy update_policy
  # [[ -z "$update_policy" ]] && zstyle ":completion:${curcontext}:" cache-policy _cap_tasks_caching_policy
  
  _arguments -C \
    {-d,--debug}'[Prompts before each remote command execution]' \
      {-e,--explain}'[Displays help (if available) for the task]:task' \
      {-F,--default-config}'[Always use default config, even with -f]' \
      {-f,--file}'[A recipe file to load. May be given more than once]:file:_files' \
      {-H,--long-help}'[Explain these options and environment variables]' \
      {-h,--help}'[Display this help message]' \
      {-l,--logger}'[Choose logger method. STDERR used by default]:file:_files' \
      {-n,--dry-run}'[Prints out commands without running them]' \
      {-p,--password}'[Immediately prompt for the password]' \
      {-q,--quiet}'[Make the output as quiet as possible]' \
      {-r,--preserve-roles}'[Preserve task roles]' \
      {-S,--set-before}'[Set a variable before the recipes are loaded]:variable' \
      {-s,--set}'[Set a variable after the recipes are loaded]:variable' \
      {-T,--tasks}'[List all tasks (matching optional PATTERN) in the loaded recipe files]:pattern' \
      {-t,--tool}'[Abbreviates the output of -T for tool integration]' \
      {-V,--version}'[Display the Capistrano version, and exit]' \
      {-v,--verbose}'[Be more verbose. May be given more than once]' \
      {-X,--skip-system-config}'[Do not load the system config file (capistrano.conf)]' \
      {-x,--skip-user-config}'[Do not load the user config file (.caprc)]' \
    '*: :->cmds' && ret=0

  # case $state in
  #   cmds)
  #     cmds=( ${(f)"$(_call_program commands cap -T 2> /dev/null | sed -e '/ # /!d; s/:/\\:/g; s/cap \([A-Za-z0-9\\:_-]*\) .*# /\1:/')"} )
  #     _describe -t commands 'cap command' cmds && ret=0
  #     ;;
  # esac

  if [[ -f config/deploy.rb ]]; then
    if (_cap_tasks_caching_policy $cache_file); then
      _call_program commands cap -T 2> /dev/null | grep '#' | cut -d " " -f 2 > $cache_file
    fi
    compadd `cat $cache_file`
  fi

  return ret
}

_cap_tasks_caching_policy() {
  [[ ! -e $1 || -f config/deploy.rb && config/deploy.rb -nt "$1" ]] && return 0
  return 1
}

_cap "$@"

filename is "_capistrano".