'a'@(1:1-1:2)
'b'@(1:2-1:3)
'x'@(1:3-1:4)
'y'@(1:4-1:5)
'c'@(1:5-1:6)
'd'@(1:6-1:7)
NLexerError@(1:7-1:7)='\n'