[antlr-interest] beginner's question

Yuxiao Hu huyuxiao at gmail.com
Tue May 24 08:30:05 PDT 2005


Hi all,
I am learning ANTLR, and tried pasting the sample program in the
editor, but antlr gives the following error message:
ANTLR Parser Generator   Version 2.7.5 (20050426)   1989-2005 jGuru.com
TokenStreamException: expecting '(', found ' '

however, it does not tell me in which line this error is.
who can tell me where the problem is?
thanks

program:

class CalcParser extends Parser;

options {
	buildAST = true;
}

expr	:	mexpr (PLUS^ mexpr)* SEMI!
	;

mexpr	:	atom (STAR^ atom)*
	;

atom	:	INT
	;

class CalcLexer extends Lexer;

WS	:	(' '
	|	'\t'
	|	'\n'
	|	'\r')
		{ _ttype = Token.SKIP; }
	;

LPAREN	:	'('
	;

RPAREN	:	')'
	;

STAR	:	'*'
	;

PLUS	:	'+'
	;

SEMI	:	';'
	;

INT	:	('0'..'9')+
	;


class CalcTreeWalker extends TreeParser;

expr	:	# (PLUS expr expr)
	|	# (STAR expr expr)
	|	INT
	;


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