@oat-sa/tao-item-runner-qti/src/scoring/processor/expressions/operators/equal.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 equal operator processor.
 * @see http://www.imsglobal.org/question/qtiv2p1/imsqti_infov2p1.html#element10654
 *
 * @author Bertrand Chevrier <bertrand@taotesting.com>
 */
import _ from 'lodash';
import errorHandler from 'taoQtiItem/scoring/processor/errorHandler';

/**
 * Process operands and returns the equal.
 * @type {OperatorProcessor}
 * @exports taoQtiItem/scoring/processor/expressions/operators/equal
 */
var equalProcessor = {
    //equality algos based on different tolerance modes
    engines: {
        exact: function (x, y) {
            return x === y;
        },
        absolute: function (x, y, includeLowerBound, includeUpperBound, tolerance) {
            var lower = includeLowerBound ? y >= x - tolerance[0] : y > x - tolerance[0],
                upper = includeUpperBound ? y <= x + tolerance[1] : y < x + tolerance[1];
            return lower && upper;
        },
        relative: function (x, y, includeLowerBound, includeUpperBound, tolerance) {
            var lower = includeLowerBound ? y >= x - (1 - tolerance[0] / 100) : y > x - (1 - tolerance[0] / 100),
                upper = includeUpperBound ? y <= x + (1 - tolerance[1] / 100) : y < x + (1 - tolerance[1] / 100);

            return lower && upper;
        }
    },

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

    operands: [],

    /**
     * Process the equal of the operands.
     * @returns {?ProcessingValue} is equal or null
     */
    process: function () {
        var result = {
            cardinality: 'single',
            baseType: 'boolean'
        };

        var attributes = this.expression.attributes || {};
        var toleranceMode = attributes.toleranceMode || 'exact';
        var engine = this.engines[toleranceMode];
        var tolerance = attributes.tolerance ? attributes.tolerance.toString().split(' ') : [];
        var includeLowerBound =
            _.isString(attributes.includeLowerBound) || _.isBoolean(attributes.includeLowerBound)
                ? this.preProcessor.parseValue(attributes.includeLowerBound, 'boolean')
                : true;
        var includeUpperBound =
            _.isString(attributes.includeUpperBound) || _.isBoolean(attributes.includeUpperBound)
                ? this.preProcessor.parseValue(attributes.includeUpperBound, 'boolean')
                : true;

        if (!_.isFunction(engine) || (['absolute', 'relative'].includes(toleranceMode) && tolerance.length === 0)) {
            return errorHandler.throw('scoring', new Error('tolerance must me specified'));
        }

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

        tolerance = _(tolerance)
            .map(function (t) {
                return equalProcessor.preProcessor.parseValue(t, 'floatOrVariableRef');
            })
            .value();

        // if only one tolerance bound is given it is used for both.
        if (tolerance.length === 1) {
            tolerance.push(tolerance[0]);
        }

        result.value = engine(
            this.preProcessor.parseVariable(this.operands[0]).value,
            this.preProcessor.parseVariable(this.operands[1]).value,
            includeLowerBound,
            includeUpperBound,
            tolerance
        );

        return result;
    }
};

export default equalProcessor;