context undo

	lex
		ignore /( ' ' | '\t')+/
		literal `* `( `) `^ `;
		token NL /'\n'/
		token id /[a-zA-Z_]+/
	end

	Map: map<item, item>

	def item 
		[id]
		{
			Map->insert( lhs, lhs )
		}
	|	[`( item* `)]
		{
			Map->insert( lhs, lhs )
		}

	def A1 []
	def A2 []

	def start 
		[A1 item* `^]
	|	[A2 item* `; NL]
	{
		for I: item in Map
			print "map el: [I]
	}

end

Undo: undo = new undo()
Undo->Map = new map<undo::item, undo::item>()

parse Input: undo::start(Undo)[ stdin ]
print( Input )

###### IN #######
a b c ( d e ) f;
###### EXP #######
map el: ( d e ) 
map el: a 
map el: b 
map el: c 
map el: d 
map el: e 
map el: f
a b c ( d e ) f;