scryer v0.5.1

scryer

This is a Typescript package that embeds Scryer Prolog.

Experimental, API will change. Currently it's (roughly) based on trealla-js's API.

npm install scryer

import { init, Prolog } from "scryer";

await init();

const pl = new Prolog();
const query = pl.query("X = 1 ; X = 2.");
for (const answer of query) {
	console.log(answer.bindings);
}

For browsers, you can use esm.sh or other CDNs to import it directly:

<script type="module">
	import { init, Prolog } from "https://esm.sh/scryer"; // ideally add version info to the URL, e.g. scryer@0.1.0
	await init();
	// query stuff
</script>

Usage

Binding variables

const answer = pl.queryOnce("X is Y * 2.", { bind: { Y: 21 } });
console.log(answer.bindings); // { X: 42, Y: 21 }

Template strings

The prolog string template literal is an easy way to escape terms. Each ${value} will be interpreted as a Prolog term.

import { prolog, Variable } from "scryer";
const answer = pl.queryOnce(
	prolog`atom_chars(${new Variable("X")}, ${"Hello!"}).`,
);
console.log(answer.bindings); // { X: Atom('Hello!') }