ANTLR3 NoViableAltException - antlr

Question

This is the part of my grammar that make error:
expr : func_name '(' constant (',' constant)* ')' ;
constant
: '"' (~'"')* '"';
WS : (' '|'\t')+ {skip();} ;
And the error is about this part of text:
"w9ygS99Qp_", "vuPfq6YcbX"
The interpreter of ANTLRWorks give me the next leaves, which have a node constant as parent:
"
w9ygS99Qp_",
"
Then it is an NoViableAltException error.
Normally, it should have this leaves:
"
w9ygS99Qp_
"
Apparently, the problem is the _ before the ", because I tried to suppress the _, but the same error appears when te parser meet the next _"

Answer 1

Your constant should be a lexer rule, not a parser rule. Inside a parser rule, ~'"' matches any token other than a double quote-token. It does not match any charatcer except the double quote-char.
Do it like this instead:
expr : func_name '(' Constant (',' Constant)* ')' ;
Constant
: '"' (~'"')* '"';
OK, thus I have to compile the grammar in Java, and then test it in Java, if I understood well?
Yes, or use ANTLRWorks' debugger instead. The debugger works like a charm.
To test in plain Java, do something like this:
import org.antlr.runtime.*;
public class Main {
public static void main(String[] args) throws Exception {
TLexer lexer = new TLexer(new ANTLRStringStream("name(\"w9ygS99Qp_\", \"vuPfq6YcbX\")"));
TParser parser = new TParser(new CommonTokenStream(lexer));
parser.expr();
}
}
Maybe should I use ANTLR4, to be able to use ANTLRWorks correctly?
If you have a choice to use either ANTLR3 or ANTLR4, then go for ANTLR4. Note that there's a new (rewritten) version of ANTLRWorks for ANTLR4 grammars: http://tunnelvisionlabs.com/products/demo/antlrworks