@masala/parser/src/test/parsec/parser_chain_test.spec.js

Masala Parser

import { describe, it, expect } from 'vitest'
import stream from '../../lib/stream/index'
import { F, C, N } from '../../lib/parsec/index'
import unit from '../../lib/data/unit'

function spaces() {
    return C.charIn(' \r\n\f\t')
        .optrep()
        .map(() => unit)
}

describe('Parser Chain Tests', () => {
    it('expect (chain) to be accepted', () => {
        const lower = C.char('x')
        const upper = F.satisfy((val) => val === 'x')
        const parser = lower.chain(upper)
        const response = parser.parse(stream.ofString('x'))
        expect(response.isAccepted()).toBe(true)
    })

    it('expect (chain) to be rejected', () => {
        const lower = C.char('x')
        const upper = F.satisfy((val) => val === 'y')
        const parser = lower.chain(upper)
        const response = parser.parse(stream.ofString('x'))
        expect(response.isAccepted()).toBe(false)
    })

    it('expect (chain) to be accepted and offset to have move', () => {
        const lower = C.char('x')
        const upper = F.satisfy((val) => val === 'x')
        const parser = lower.chain(upper)
        const response = parser.parse(stream.ofString('x'))
        expect(response.offset).toBe(1)
    })

    it('expect (chain) to be accepted and offset to have move more', () => {
        const lower = C.string('xyz')
        const upper = F.satisfy((val) => val === 'xyz')
        const parser = lower.chain(upper.then(upper))
        const response = parser.parse(stream.ofString('xyzxyz'))
        expect(response.offset).toBe(2)
    })

    it('expect (chain) to be find back the source offset', () => {
        const lower = C.string('xyz')
        const upper = F.satisfy((val) => val === 'xyz')
        const parser = lower.chain(upper.then(upper))
        const response = parser.parse(stream.ofString('xyzxyz'))
        expect(response.input.source.offsets[response.offset]).toBe(6)
    })

    it('expect (chain) to be accepted again', () => {
        const p1 = N.number().thenLeft(C.char(' ').opt())
        const p2 = F.any()
            .then(F.any())
            .thenLeft(F.eos())
            .map(function (r) {
                return r[0] + r[1]
            })
        expect(
            p1.chain(p2).parse(stream.ofString('12 34'), 0).isAccepted(),
        ).toBe(true)
    })

    it('expect (chain) to return 46', () => {
        const p1 = N.number().thenLeft(C.char(' ').opt())
        const p2 = F.any()
            .then(F.any())
            .thenLeft(F.eos())
            .array()
            .map(function (r) {
                return r[0] + r[1]
            })
        expect(p1.chain(p2).parse(stream.ofString('12 34'), 0).value).toBe(46)
    })

    it('expect (chain) to add multiple numbers', () => {
        const token = N.number().then(spaces().opt().drop()).single()
        const lex = F.satisfy((number) => number > 0)
            .rep()
            .map((values) => values.array().reduce((acc, n) => acc + n, 0))

        const parsing = token.chain(lex).parse(stream.ofString('10 12 44'), 0)

        expect(parsing.isEos()).toBe(true)
        expect(parsing.value).toBe(66)
    })

    it('expect (chain) to be not satisfied by upper level', () => {
        const token = N.number().then(spaces().opt().drop())
        const lex = F.satisfy((number) => number > 0)
            .rep()
            .map((values) => values.array().reduce((acc, n) => acc + n, 0))

        const parsing = token.chain(lex).parse(stream.ofString('10 -12 44'), 0)

        expect(parsing.isEos()).toBe(false)
    })
})