PARSER_BEGIN(parens1) public class parens1 { public static int pairs_of_parens = 0; public static void main(String args[]) throws ParseException { int result; parens1 parser = new parens1(System.in); parser.parentheses(); System.out.println("Pairs of parentheses = " + parser.pairs_of_parens); } } PARSER_END(parens1) SKIP : { " " | "\n" } TOKEN : { < LPAREN: "(" > | < RPAREN: ")" > } void parentheses(): {} { <LPAREN> parentheses() <RPAREN> { pairs_of_parens++; } | { } }