# ==============================================================================
# 
# 	RubyFORTH -- Copyright (C) 2007-8, Marc Simpson (GPL). 
# 
#	Implementation of 'forget'. To use, 'ruby-include demos/forget.rb'
# 
# ==============================================================================

def forget_wordlist_headers(wordlist)
  wordlist.each { |k,v| wordlist.delete(k) if v > $here  }
end

def forget_headers(vocab)
  forget_wordlist_headers(vocab[0])
  forget_wordlist_headers(vocab[1])
end

def forget(xt)
  if xt == 0 
    print "Error: word not found."
    return
  end
  $here = xt - 1
  $vocabularies.each { |v| forget_headers(v) }
end

prim "forget" , "forget(xt(parse_word))"