Constraint Lingo

Constraint Lingo is a high-level logic-programming language for expressing tabular constraint problems such as those found in logic puzzles. Raphael Finkel developed it starting around 2000 as part of work in Logic Programming with Mirek Truszczynski and Victor Marek.

Example
  Puzzle
  Translation into Constraint Lingo
  Solution
How it all works
How fast is it?
How general is Constraint Lingo?
It's available for download
You can try a puzzle yourself
Documentation

A small example

How it all works

A compiler translates the Constraint-Lingo program into low-level code, which is then executed by a logic engine. A post-processor formats the result into a table.

How fast is it?

The compiler and post-processors are so fast that we never worry about their contribution to the total time. Almost all the 90 or so puzzles we have programmed are solved in less than a second by all versions of the compiler and their associated logic engines. A few take more than 10 seconds with some compilers.

How general is Constraint Lingo?

We are able to encode several graph problems in Constraint Lingo, notably 3-coloring, Hamiltonian paths/circuits, and independent sets. A preprocessor converts graphs into equivalent Constraint-Lingo programs.

We continue to develop Constraint Lingo. We are currently adding mappings between solution rows, multiple-selection classes, and limited function symbols.

It's available for download

You can download a copy of our current work from ftp://ftp.cs.uky.edu/cs/software/cl.tar.gz. This code is not production quality; it is work in progress. We would appreciate knowing you have downloaded it and what your experiences are; please mail to raphael_@cs.uky.edu (without the underscore).

You can try a puzzle yourself

Upload from this file:
or enter your Constraint Lingo program here:

Documentation

We have written several papers on Constraint Lingo. The most current one in Software -- Practice and Experience, Volume 34, number 15, pages 1481-1504, December 2004.

This page has been translated into French by Mary Orban.