@masala/parser/src/lib/data/tuple.js

Masala Parser

/*
 * Parsec
 * https://github.com/d-plaindoux/parsec
 *
 * Copyright (c) 2015-2016 Didier Plaindoux
 * Licensed under the LGPL3 license.
 */

export const NEUTRAL = Symbol('MASALA_NEUTRAL')

export class Tuple {
    constructor(array) {
        if (array === undefined) {
            array = []
        }
        this.value = array
    }

    at(index) {
        return this.value[index]
    }

    array() {
        return [...this.value]
    }

    single() {
        return this.value[0]
    }

    first() {
        return this.value[0]
    }

    last() {
        return this.value[this.size() - 1]
    }

    join(j = '') {
        return this.value.join(j)
    }

    append(element) {
        if (element === NEUTRAL) {
            return new Tuple([...this.value])
        }
        if (isTuple(element)) {
            return new Tuple([...this.value, ...element.value])
        }
        // single element
        return new Tuple([...this.value, element])
    }

    isEmpty() {
        return this.size() === 0
    }

    size() {
        return this.value.length
    }
}

export function isTuple(object) {
    return object instanceof Tuple
}

export function tuple(array) {
    if (array === undefined) {
        return new Tuple([])
    } else {
        return new Tuple(array)
    }
}