# Parse a full sequence of tokens and return a complete syntactic tree
	fun parse: Node
	do
		state = start_state
		state_stack.clear
		node_stack.clear
		stop = false
		while not stop do
			#print "* current state {state}"
			#print "  tokens={tokens.join(" ")}"
			#print "  node_stack={node_stack.join(" ")}"
			#print "  state_stack={state_stack.join(" ")}"
			state.action(self)
		end
		#print "* over"
		return node_stack.first
	end