Hi Bijan,

Please ask further questions in the Moose mailing-list, other people might be interested too.

I'm trying to understand how PetitParser initializes grammar classes (the tutorial doesn't make it clear how to use def: in a class context). I see now that mutual recursive productions should work out of the box.

You don't need #def: in the context of PPCompositeParser, the framework does that for you. See the class comment of PPCompositeParser for additional information.

However, while figuring this out, I noticed this following bit:

...

parser := PPUnresolvedParser named: aSymbol.        productionIndexesAndNames do: [ :assoc |                self instVarAt: assoc key put: (PPUnresolvedParser named: assoc value) ].        parser := self perform: aSymbol. ...

It seems that the last line of the snippet should read:        parser def: (self perform: aSymbol).

Yes, you are right. I changed that in the latest version.

However, consider not to loop into the start state. You get a more reusable model if you use 'parser' simply as a selector of where to start the grammar (e.g. the method, the method declaration, or the expression in the example of Smalltalk).

Lukas

This would be consistent with how the rest of the productions initialize themselves and wouldn't make the first line of the snippet pointless.

I can't really discern any difference in commenting out line one, leaving everything as is, or shifting the last bit to def: So I'm missing something!

Cheers, Bijan.