Extending Casl by Late Binding

We deene an extension of Casl, the standard language for algebraic speciication, with a late binding mechanism. More precisely, we introduce a special kind of functions called methods, for which, diierently to what happens for usual functions, overloading resolution is delayed at evaluation time and not required to be conservative. The extension consists, at the semantic level, in the deenition of an institution LB supporting late binding which is deened on top of the standard subsorted institution of Casl and, at the linguistic level, in the enrichment of the Casl language with appropriate constructs for dealing with methods. In addition to this, we propose a further enrichment of the Casl language which is made possible by introduction of late binding, that is a mechanism for \inheriting" axioms from a supersort with the possibility of overriding them. The aim is to obtain advantages in terms of reuse of speciications similar to those obtained by inheritance in object-oriented programming languages.