Logic-db NPM | npm.io

LogicDB

Embedding a Prolog-like logic programming language in JavasScript and TypeScript.

Combining logic programming and database management.
Can declare relations between JSON documents.
Well typed relation in TypeScript.
Practical and simple API.

Install

npm i logic-db

Usage

import Logic, { v, ne, ty } from "logic-db"

// NOTE Drinking Pairs -- example from "Clause and Effect"

const drinks = new Logic.Table({
  name: "drinks",
  schema: ty.object({
    person: ty.string(),
    alcohol: ty.string(),
  }),
})

drinks.i({ person: "john", alcohol: "martini" })
drinks.i({ person: "mary", alcohol: "gin" })
drinks.i({ person: "susan", alcohol: "vodka" })
drinks.i({ person: "john", alcohol: "gin" })
drinks.i({ person: "fred", alcohol: "gin" })
drinks.i({ person: "fred", alcohol: "vodka" })

const pair = new Logic.Table({
  name: "pair",
  schema: ty.object({
    p1: ty.string(),
    p2: ty.string(),
    alcohol: ty.string(),
  }),
})

pair.i({ p1: v`p1`, p2: v`p2`, alcohol: v`alcohol` }, (v) => [
  drinks.o({ person: v`p1`, alcohol: v`alcohol` }),
  drinks.o({ person: v`p2`, alcohol: v`alcohol` }),
  ne(v`p1`, v`p2`),
])

console.log(pair.query({ p1: v`x`, p2: "mary", alcohol: "gin" }))
console.log(pair.query({ p1: v`x`, p2: v`y`, alcohol: "gin" }))
console.log(pair.query({ p1: v`x`, p2: v`y`, alcohol: v`alcohol` }))