parjs/dist/internal/combinators/then.js

Library for building parsers using combinators.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.then = exports.thenq = exports.qthen = void 0;
const result_1 = require("../result");
const combinated_1 = require("../combinated");
const wrap_implicit_1 = require("../wrap-implicit");
const combinator_1 = require("./combinator");
const map_1 = require("./map");
/**
 * Applies the source parser followed by `next`. Yields the result of `next`.
 *
 * @param next
 */
function qthen(next) {
    return (0, combinator_1.composeCombinator)(then(next), (0, map_1.map)(arr => arr[1]));
}
exports.qthen = qthen;
/**
 * Applies the source parser followed by `next`. Yields the result of the source parser.
 *
 * @param next
 */
function thenq(next) {
    return (0, combinator_1.composeCombinator)(then(next), (0, map_1.map)(arr => arr[0]));
}
exports.thenq = thenq;
class Then extends combinated_1.Combinated {
    constructor(source, _rest) {
        super(source);
        this._rest = _rest;
        this.type = "then";
        this.expecting = this.source.expecting;
        this._seq = [this.source, ...this._rest];
    }
    _apply(ps) {
        const results = [];
        const { _seq } = this;
        const origPos = ps.position;
        for (const cur of _seq) {
            cur.apply(ps);
            if (ps.isOk) {
                results.push(ps.value);
            }
            else if (ps.isSoft && origPos === ps.position) {
                // if the first parser failed softly then we propagate a soft failure.
                return;
            }
            else if (ps.isSoft) {
                ps.kind = result_1.ResultKind.HardFail;
                // if a i > 0 parser failed softly, this is a hard fail for us.
                // also, propagate the internal expectation.
                return;
            }
            else {
                // ps failed hard or fatally. The same severity.
                return;
            }
        }
        ps.value = results;
        ps.kind = result_1.ResultKind.Ok;
    }
}
function then(...parsers) {
    const resolvedParsers = parsers.map(wrap_implicit_1.wrapImplicit);
    return source => {
        return new Then((0, wrap_implicit_1.wrapImplicit)(source), resolvedParsers);
    };
}
exports.then = then;
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