Table of Contents
The Java programming language defines the signature of a method. The XL programming language introduces class predicates (Chapter 12, Class Predicates) which also have a signature. This chapter defines the common terms and operations on signatures: Argument transformations, applicability, and specificity. They are used in the context of a signature invocation, which is either a method invocation (Section 16.2, “Method Invocation Expressions”) or the usage of a class predicate in a query (Section 17.4.9, “Class Predicates”). A signature invocation provides a set of explicit argument expressions.
Some syntactic contexts provide an argument transformation for signature invocations or even a set of alternatives of argument transformations. Such transformations alter the explicit argument expressions to the actual argument expressions. This may contain, e.g., the addition of implicit arguments. The alternatives of argument transformations have an effect on the applicability of signatures.