  We present a metagrammatical formalism, {\em generic rules}, to give a
default interpretation to grammar rules. Our formalism introduces a process of
{\em dynamic binding} interfacing the level of pure grammatical knowledge
representation and the parsing level. We present an approach to non-constituent
coordination within categorial grammars, and reformulate it as a generic rule.
This reformulation is context-free parsable and reduces drastically the search
space associated to the parsing task for such phenomena.
