"use strict";

const { NoMatch } = require("../symbols");

module.exports = function* either(instruction, state, context) {
	let { options } = instruction;

	for (let option of options) {
		let result = yield option;

		if (result === NoMatch) {
			// Restore index and try again with the next option
			state.currentIndex = context.startIndex;
			continue;
		} else {
			// Don't restore index; the match has been consumed
			return result;
		}
	}

	// None of the options matched
	return NoMatch;
};