A Comparison for Unification-Based Parsers

Manuel Vilares Ferro
David Cabrero Souto
Miguel Angel Alonso Pardo

in M. Falaschi, J. L. Freire and M. Vilares (eds.), Proc. of APPIA-GULP-PRODE'98 Joint Conference on Declarative Programming, pp. 113-123, Corunna, Spain, 1998.


Unification-based grammars have been the object of study in computational linguistics over the last few years with the intention of creating powerful parsing environments. However, it is not common to find practical studies about what the real interest of these techniques is, and which approaches are better adapted in each case.

We attempt to justify the practical consideration of dynamic programming in the continuum of Horn-like formalisms, showing that conclusions attained for definite clause grammars are a natural extension of the same conclusions in context-free theory. Our aim is to demonstrate the practical interest of this technology, suggesting a simple decision guide for the interested reader.

Keywords: Parsing, dynamic programming, push-down automata, static analysis, structure sharing.

Manuel Vilares Ferro / vilares@dc.fi.udc.es
David Cabrero Souto / cabrero@dc.fi.udc.es
Miguel Angel Alonso Pardo / alonso@dc.fi.udc.es