namespace r1

	lex
		literal '!', 'a', 'b'
		ignore /[ \n\t]+/
	end

	def line [ '!' 'a' 'b' 'b' 'a']

end r1

namespace r2

	lex
		literal '!'
		token id /[a-zA-Z_]+/
		ignore /[ \n\t]+/
	end

	def line [ '!' id ]

end r2

def item 
	[r1::line]
|	[r2::line]

def btscan 
	[item*]

cons Parser: parser<btscan> []

send Parser "!ab"
send Parser "b "
send Parser "!ab"
send Parser "ba !aab\n"

print_xml( Parser() )