Logic programming beyond Prolog release_xvor3e7j5fdu7a7eki7q4cdk4e

by M.H. van Emden

Released as a report .

2014  

Abstract

A logic program is an executable specification. For example, merge sort in pure Prolog is a logical formula, yet shows creditable performance on long linked lists. But such executable specifications are a compromise: the logic is distorted by algorithmic considerations, yet only indirectly executable via an abstract machine. This paper introduces relational programming, a method that solves the difficulty with logic programming by a separation of concerns. It requires three texts: (1) the axioms, a logical formula that specifies the problem and is not compromised by algorithmic considerations, (2) the theorem, a logical formula that expresses the idea of the algorithm and follows from the axioms, and (3) the code, a transcription of the theorem to a procedural language. Correctness of the code relies on the logical relationship of the theorem with the axioms and relies on an accurate transcription of the theorem to the procedural language. Sorting is an example where relational programming has the advantage of a higher degree of abstractness: the data to be sorted can be any data type in C++ (the procedural language we use in our examples) that satisfies the axioms of linear order, while the pure-Prolog version is limited to data structures in the form of linked cells. We show another advantage of relational programs: they have a model-theoretic and fixpoint semantics equivalent to each other and analogous to those of pure Prolog programs.
In text/plain format

Archived Files and Locations

application/pdf  258.6 kB
file_77dyaj3h6nb7tov5ldnqnvge5a
arxiv.org (repository)
web.archive.org (webarchive)
Read Archived PDF
Preserved and Accessible
Type  report
Stage   submitted
Date   2014-12-10
Version   v1
Language   en ?
Number  DCS-355-IR
arXiv  1412.3480v1
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: 3f5abb2d-33bc-4045-a238-0fe1c907bc15
API URL: JSON