Timed Definite Clause Omega-Grammars

We propose timed context-free grammars (TCFGs) and show how parsers for such grammars can be developed using denite clause grammars (DCGs) coupled with constraints over reals (CLP(R)). Timed context-free grammars describe timed context- free languages (TCFLs). We next extend timed context-free grammars to timed context- free !-grammars (!-TCFGs for brevity) and incorporate co-inductive logic programming in DCGs to obtain parsers for them. Timed context-free !-grammars describe timed context- free languages containing innite-sized words, and are a generalization of timed !-regular languages recognized by timed automata. We show a practical application of !-TCFGs to the well-known generalized railroad crossing problem.