#!/usr/bin/env zsh

() {
  emulate -L zsh -o extended_glob
  [[ $_z4h_word_prefix != *('$'|'\') ]] || return
  if [[ $_z4h_word_prefix == *[A-Z]* ]]; then
    [[ -z ${(@)*:#$_z4h_word_prefix*} ]] || return
  else
    [[ -z ${(@)*:#(#i)$_z4h_word_prefix*} ]] || return
  fi
} "$@" || _z4h_word_prefix=
_z4h_word_prefix=${_z4h_word_prefix// /\\ }