chr/test/jit-compiler/propagation.js

Interpreter for Constraint Handling Rules (CHR) in JavaScript

const test = require('tape')

const CHR = require('../../src/index')

test('a ==> b', function (t) {
  const chr = new CHR()
  chr('a ==> b')

  chr.a().then(function () {
    t.equal(chr.Store.length, 2)
    t.end()
  })
})

test('a ==> b, c', function (t) {
  const chr = new CHR()
  chr('a ==> b, c')

  chr.a().then(function () {
    t.equal(chr.Store.length, 3)
    t.end()
  })
})

test('a, b ==> c', function (t) {
  const chr = new CHR()
  chr('a, b ==> c')

  chr.a().then(function () {
    t.equal(chr.Store.length, 1)

    chr.c().then(function () {
      t.equal(chr.Store.length, 2)

      chr.b().then(function () {
        t.equal(chr.Store.length, 4)
        t.end()
      })
    })
  })
})

test('a ==> b', function (t) {
  const chr = new CHR()
  chr('a ==> b')

  Promise.all([
    chr.a(),
    chr.a()
  ]).then(function () {
    t.equal(chr.Store.length, 4)
    t.end()
  })
})

test('a(N) ==> b(N+1,N+2)', function (t) {
  const chr = new CHR()
  chr('a(N) ==> b(N+1,N+2)')

  Promise.all([
    chr.a(1),
    chr.a(2)
  ]).then(function () {
    t.equal(chr.Store.length, 4)
    t.end()
  })
})

test('a(N) ==> N <= 4 | a(N+1)', function (t) {
  const chr = new CHR()
  chr('a(N) ==> N <= 4 | a(N+1)')

  chr.a(1).then(function () {
    t.equal(chr.Store.length, 5)
    t.end()
  })
})

test('a, a ==> b', function (t) {
  const chr = new CHR()
  chr('a, a ==> b')

  chr.a().then(function () {
    t.equal(chr.Store.length, 1, 'Rule not fired')
    t.end()
  })
})

test('a(0), b ==> c', function (t) {
  const chr = new CHR()
  chr('a(0), b ==> c')

  chr.b().then(function () {
    t.equal(chr.Store.length, 1, 'Rule not fired')

    chr.a(3).then(function () {
      t.equal(chr.Store.length, 2, 'Rule not fired')

      chr.b().then(function () {
        t.equal(chr.Store.length, 3, 'Rule not fired')

        chr.a(0).then(function () {
          t.equal(chr.Store.length, (3 + 1 + 2), "Rule fired for both b's")

          t.end()
        })
      })
    })
  })
})