@oat-sa/tao-item-runner-qti/src/scoring/processor/expressions/operators/equalRounded.js

TAO QTI Item Runner modules

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; under version 2
 * of the License (non-upgradable).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (c) 2015-2019 (original work) Open Assessment Technlogies SA (under the project TAO-PRODUCT);
 *
 */

/**
 * The equalRounded operator processor.
 * @see http://www.imsglobal.org/question/qtiv2p1/imsqti_infov2p1.html#element10664
 *
 * @author Bertrand Chevrier <bertrand@taotesting.com>
 */
import _ from 'lodash';
import errorHandler from 'taoQtiItem/scoring/processor/errorHandler';

/**
 * Process operands and returns equalRounded result.
 * @type {OperatorProcessor}
 * @exports taoQtiItem/scoring/processor/expressions/operators/equalRounded
 */
var equalRoundedProcessor = {

    engines: {
        significantFigures: function(value, exp) {
            return decimalAdjust('round', value, exp);
        },
        decimalPlaces: function(value, exp) {
            return decimalAdjust('floor', value, exp);
        }
    },

    constraints: {
        minOperand: 2,
        maxOperand: 2,
        cardinality: ['single'],
        baseType: ['integer', 'float']
    },

    operands: [],

    /**
     * @returns {?ProcessingValue} a single boolean
     */
    process: function() {

        var attributes = this.expression.attributes || {};
        var roundingMode = attributes.roundingMode || 'significantFigures';
        var roundingEngine = _.isFunction(this.engines[roundingMode]) ? this.engines[roundingMode] : this.engines.significantFigures;
        var figures = this.preProcessor.parseValue(this.expression.attributes.figures, 'integerOrVariableRef');
        var op1, op2;
        var result = {
            cardinality: 'single',
            baseType: 'boolean'
        };

        if (!this.preProcessor.isNumber(figures)) {
            errorHandler.throw('scoring', new Error('figures must me numeric'));
            return null;
        }

        if (figures <= 1 && roundingMode === 'significantFigures') {
            errorHandler.throw('scoring', new Error('significantFigures must me numeric'));
            return null;
        }

        //if at least one operand is null, then break and return null
        if (_.some(this.operands, _.isNull) === true) {
            return null;
        }

        op1 = this.preProcessor.parseVariable(this.operands[0]).value;
        op2 = this.preProcessor.parseVariable(this.operands[1]).value;

        result.value = roundingEngine(op1, figures) === roundingEngine(op2, figures);

        return result;
    }
};

/**
 * Decimal adjustment of a number.
 *
 * @param {String}  type  The type of adjustment.
 * @param {Number}  value The number.
 * @param {Integer} exp   The exponent (the 10 logarithm of the adjustment base).
 * @returns {Number} The adjusted value.
 * @private
 */
function decimalAdjust(type, value, exp) {

    // Shift
    value = value.toString().split('e');
    value = Math[type](+(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp)));

    // Shift back
    value = value.toString().split('e');
    return +(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp));
}

export default equalRoundedProcessor;