ASF: an algebraic specification formalism
Jan Aldert Bergstra, Jan Heering, Paul Klint · Centrum Wiskunde & Informatica (CWI), the national research institute for mathematics and computer science in the Netherlands · 1987
The algebraic specification formalism ASF supports modularized (first-order) equational specifications. Among its features are {a) import and parameterization of modules; (b) hidden (auxiliary) sorts and functions; (c) positive conditional equations; (d) overloaded functions; (e) infix operators.Most of the context-dependent errors in ASF specifications are violations of the so-called origin rule.Besides catching errors, this rule enforces a certain modularization of ASF specifications.The meaning of the modularization constructs of ASF is defined by means of a syntactical normalization procedure.Numerous examples of both correct and incorrect ASF specifications are given in an appendix.