module RDoc::Parser::RubyTools

def add_token_listener(obj)
  @token_listeners ||= []
  @token_listeners << obj
end

def get_tk
  tk = nil
  if @tokens.empty? then
    if @scanner_point >= @scanner.size
      return nil
    else
      tk = @scanner[@scanner_point]
      @scanner_point += 1
      @read.push tk[:text]
    end
  else
    @read.push @unget_read.shift
    tk = @tokens.shift
  end
  if tk == nil || :on___end__ == tk[:kind]
    tk = nil
  end
  return nil unless tk
  # inform any listeners of our shiny new token
  @token_listeners.each do |obj|
    obj.add_token(tk)
  end if @token_listeners
  tk
end

def get_tk_until(*tokens)
  read = []
  loop do
    tk = get_tk
    case tk
    when *tokens then
      unget_tk tk
      break
    end
    read << tk
  end
  read
end

def get_tkread
  read = @read.join("")
  @read = []
  read
end

def peek_read
  @read.join('')
end

def peek_tk
  unget_tk(tk = get_tk)
  tk
end

def remove_token_listener(obj)
  @token_listeners.delete(obj)
end

def reset
  @read       = []
  @tokens     = []
  @unget_read = []
  @nest = 0
  @scanner_point = 0
end

def skip_tkspace
  tokens = []
  while (tk = get_tk) and (:on_sp == tk[:kind] or :on_nl == tk[:kind] or :on_ignored_nl == tk[:kind]) do
    tokens.push(tk)
  end
  unget_tk(tk)
  tokens
end

def skip_tkspace_without_nl
  tokens = []
  while (tk = get_tk) and :on_sp == tk[:kind] do
    tokens.push(tk)
  end
  unget_tk(tk)
  tokens
end

def token_listener(obj)
  add_token_listener obj
  yield
ensure
  remove_token_listener obj
end

def unget_tk(tk)
  @tokens.unshift tk
  @unget_read.unshift @read.pop
  # Remove this token from any listeners
  @token_listeners.each do |obj|
    obj.pop_token
  end if @token_listeners
  nil
end