Abstract
We propose a novel approach to semantics driven disambiguation based on Attribute Grammars (AGs). AGs share the same modularity model as its host grammar language, here Syntax Definition Formalism (SDF), what makes them particularly attractive for working on unstable grammars, or grammar extensions. The framework we propose is effective, since a full ISO-C99 disambiguation chain already works, and the core of the hardest ambiguities of C++ is solved. This requires specific techniques, and some extensions to the stock AG model.