node-less/lib/operation.js

Less Compiler For Node

(function (module) {

    var Dimension = require('./dimension.js'),
        Color = require('./color.js');

    var Operation = function (op, operands, isSpaced) {
        this.op = op.trim();
        this.operands = operands;
        this.isSpaced = isSpaced;
    };

    Operation.prototype = {
        type: "Operation",
        accept: function (visitor) {
            this.operands = visitor.visit(this.operands);
        },
        eval: function (env) {
            var a = this.operands[0].eval(env),
                b = this.operands[1].eval(env),
                temp;

            if (env.isMathOn()) {
                if (a instanceof Dimension && b instanceof Color) {
                    if (this.op === '*' || this.op === '+') {
                        temp = b, b = a, a = temp;
                    } else {
                        throw { type: "Operation",
                                message: "Can't substract or divide a color from a number" };
                    }
                }
                if (!a.operate) {
                    throw { type: "Operation",
                            message: "Operation on an invalid type" };
                }

                return a.operate(env, this.op, b);
            } else {
                return new Operation(this.op, [a, b], this.isSpaced);
            }
        },
        toCSS: function (env) {
            var separator = this.isSpaced ? " " : "";
            return this.operands[0].toCSS() + separator + this.op + separator + this.operands[1].toCSS();
        }
    };

    module.exports = Operation;

})(module);