1 2 grammar t058rewriteAST63; 3 options {language=JavaScript;output=AST;} 4 tokens {BLOCK;} 5 a : x+=ID (y=b)? -> ($x $y)?; 6 b : ID ; 7 ID : 'a'..'z'+ ; 8 WS : (' '|'\n') {$channel=HIDDEN;} ;