node-swipl

A node.js interface to the SWI-Prolog library. A fork of node-prolog-swi.

For now, this addon supports the creation of rules and facts 'on the fly' and querying.

The SWI-Prolog library requires the SWI_HOME_DIR environment variable to be set (See http://www.swi-prolog.org/FAQ/FindResources.html). Thus an example call could be:

SWI_HOME_DIR=/usr/lib/swi-prolog node tests/a.js

Missing SWI_HOME_DIR will result in

[FATAL ERROR:
    Could not find system resources]

Now builds with node-gyp (Thanks to Johny Jose):

$ node-gyp configure
$ SWI_HOME_DIR=/usr/lib/swi-prolog node-gyp build 

After building, try running:

$ SWI_HOME_DIR=/usr/lib/swi-prolog NODE_PATH=build/Release node tests/a.js

If you like it, use and/or fork it. Corrections and improvements are welcome.

Basic usage

Initialization

var swipl = require('swipl');
swipl.initialise();

Create module

var m = swipl.module("mymod");

Facts and rules (shortcut for m.call_predicate("assert", [ term ]))

m.assert("likes(romeo, julia).");
{}

Querying - Single solution

m.call_predicate("likes", ["romeo", "X"]);
{ X: 'julia' }

Querying - Query

m.assert("likes(john, julia).");
{}
var q = m.open_query("likes", ["X", "julia"]);
undefined
q.next_solution();
{ X: 'romeo' }
q.next_solution();
{ X: 'john' }
q.next_solution();
false
q.close();
true

Cleanup

swipl.cleanup();