Subset-equational Language

The Subset-equational language (SEL) is a declarative programming language for set processing, written by Bharat Jayaraman.

Features include:

• subset and equational program clauses.
• pattern matching over sets (supporting efficient iteration over sets).
• annotations to say which functions distribute over union in which arguments (for point-wise/incremental computation over sets).
• defining transitive closures through circular constraints (implemented by mixed top-down/memoisation and bottom-up strategy).
• metaprogramming and simple higher-order programming.
• modest user-interface including tracing.

The SEL compiler, written in Quintus Prolog, generates WAM-like code, extended to deal with set-matching, memoisation, and the novel control structure of the language. The run-time system is written in C.

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.