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` }))

Examples

Clause and Effect

• By William F. Clocksin.

Structure and Interpretation of Computer Programs (SICP)

• By Harold Abelson and Gerald Jay Sussman.
• It has one section about logic programming:
  • sarabander-sicp
  • official

The Power of Prolog

• An excellent modern teaching of Prolog, by Markus Triska.

API Docs

TODO

Contributions

Be polite, do not bring negative emotion to others.

• TODO.md
• STYLE-GUIDE.md
• CODE-OF-CONDUCT.md
• When contributing, add yourself to AUTHORS

License

• GPLv3