Hi.

I'm trying to accumulate syntax and semantic errors in my parser and tree walker so that I can display them as a list. It's working fine in my parser, but not my tree walker.

This is the relevant parser code:

			

			class ThingParser extends Parser;
			

			options {
			

			exportVocab=Thing;
			

			defaultErrorHandler=false;
			

			k=4;
			

			buildAST=true;
			

			}
			

			

			{
			

			List syntaxErrors = new ArrayList();
			

			}
			

			

			schemaCreation:
			

			{
			

			syntaxErrors.clear();
			

			}
			

			(creationStatement)* EOF!
			

			{
			

			if (!syntaxErrors.isEmpty()) {
			

			throw new ParseException((ParseError[]) syntaxErrors.toArray(new ParseError[syntaxErrors.size()]));
			

			}
			

			}
			

			;
			

			

			protected creationStatement:
			

			(
			

			THING thingCreation
			

			| ANOTHER_THING anotherThingCreation
			

			)
			

			(SEMICOLON!)?
			

			; exception
			

			catch [RecognitionException re] {
			

			syntaxErrors.add(new ParseError(re.getLine(), re.getColumn(), re.getMessage()));
			

			BitSet bits = new BitSet(Math.max(THING, ANOTHER_THING));
			

			bits.add(THING);
			

			bits.add(ANOTHER_THING);
			

			consumeUntil(bits);
			

			}
			

		

This works fine (it accumulates a list of errors, and at the EOF, it throws a ParseException if there were any errors).

I've tried something similar in my tree walker. Here's the code:

			

			class ThingTreeWalker extends TreeParser;
			

			options {
			

			importVocab=Thing;
			

			defaultErrorHandler=false;
			

			k=1;
			

			buildAST=false;
			

			}
			

			

			{
			

			List errors = new ArrayList();
			

			}
			

			

			schemaCreation[Schema schema]:
			

			{
			

			errors.clear();
			

			}
			

			

			(creationStatement[schema])*
			

			

			{
			

			if (errors.size() > 0) {
			

			throw new ParseException((ParseError[]) errors.toArray(new ParseError[errors.size()]));
			

			}
			

			}
			

			;
			

			

			protected creationStatement[Schema schema]:
			

			thingCreation[schema]
			

			| anotherThingCreation[schema]
			

			; exception
			

			catch [SchemaException sex] {
			

			errors.add(new ParseError(sex.getMessage()));
			

			}
			

		

There's no consumeUntil() since TreeParser doesn't have this method. Also in this case, rather than RecognitionExceptions, there are my own SchemaExceptions.

The problem is that when the creationStatement rule is terminated early by a SchemaException the schemaCreation rule subsequently exits (i.e. it throws a ParseException with the single ParseError). Since I'm trying to collect all of the errors, this exit occurs too early.

Can anyone help?

Lance