[antlr-interest] Yacc to antlr guide?

Christopher Nebel c.nebel at apple.com
Fri Nov 14 00:50:24 PST 2003


Is there documentation somewhere on how to translate yacc grammars into 
antlr?  I've got a non-trivial yacc-based grammar I'd like to port.  
Most of the basic grammar parts are straightforward, if tedious, but 
I'm having two specific problems:

1. How do I deal with operator precedence?  The yacc grammar uses 
precedence declarations, and I don't see any equivalent.  Obviously, I 
could break the big rules apart into smaller ones that reflect the 
precedence, but I'm hoping for something more direct.

2. The actions in the original make heavy use of $[$12...], and it's 
not clear to me how to deal with that.  Well, it kind of is.  I can see 
the "rule returns [T v]" bit, but I'm not looking forward to adding 
that to every single rule -- is there some way to say that all rules 
return a T without decorating each of them individually?  The custom 
AST stuff is also sort of applicable, but I've got a bunch of weird 
constraints (notably the fact that the type is *not* a C++ object) that 
make using it somewhat impractical.

Thanks,

--Chris Nebel


 

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