Constraints and Logic Programming in Grammars and Language Analysis

Constraints are an important notion in grammars and language analysis, and constraint programming techniques have been developed concurrently for solving a variety of complex problems. In this chapter we consider the synthesis of these branches into practical and effective methods for language analysis. With a tool such as Constraint Handling Rules, CHR, to be ex- plained below, the grammar writer or programmer working with language analysis can define his or her own constraint solvers specifically tailored for the linguistic problems at hand. We concentrate on grammars and lan- guage analysis methods that combine constraints with logic grammars such as Definite Clause Grammars and CHR Grammars, and show also a direct relationship to abductive reasoning.