[antlr-interest] ANTLR3.0b5 - Embedding on parser within another one (Parser nesting)

[alexander.berger at finnova.ch]

Hi 

I have two parsers and want to embed on parser within the other. But somehow
I don't get it. I expected it to work like this:


start : 
	x=subParser -> $x.expression
	;


subParser returns [Expression expression] : 
		'do' { 
			PLangParser p = new PLangParser(this.getTokenStream());
			p.setTreeAdaptor(this.getTreeAdaptor());
			$subParser.expression = (Expression)p.start().getTree();		}
	;


but in the rewrite instruction '-> $x.expression' antlr complains with the following error message:

error(100): PLang.g3:111:19: syntax error: antlr: PLang.g3:111:19: unexpected token: .

In other words, in the rewrite instruction "x=subParser -> $x.expression"
antlr does not allow to use the return value as output Tree.

I haven't found a solution on the WIKI page so I am curious if this kind
of parser embedding is possible or not with antlr3. 

Has anybody ever tried to do something similar?

Kind regards
Alex
____________________________________________

finnova AG Bankware
Alexander Berger
SR-Peripheral-Team 

Sägestrasse 22, CH-5600 Lenzburg
Tel: +41 62 886 4807 / Fax: +41 62 886 4888 mailto:alexander.berger at finnova.ch
http://www.finnova.ch