Generalized Register Context-Free Grammars

Abstract

Register context-free grammars (RCFG) is an extension of context-free grammars to handle data values in a restricted way. This paper first introduces register type as a finite representation of the register contents and shows some properties of RCFG. Next, generalized RCFG (GRCFG) is defined by permitting an arbitrary relation on data values in the guard expression of a production rule. We extend register type to GRCFG and introduce two properties of GRCFG, the simulation property and the type oracle. We then show that \(\varepsilon \)-rule removal is possible and the emptiness and membership problems are EXPTIME solvable for GRCFG that satisfy these two properties.