Method ev

src/common/style/CartoCSS.js:3929–4003

(env)

    }

    ev(env) {
        var a = this.operands[0].ev(env),
            b = this.operands[1].ev(env),
            temp;

        if (a.is === 'undefined' || b.is === 'undefined') {
            return {
                is: 'undefined',
                value: 'undefined'
            };
        }

        if (a instanceof CartoCSS.Tree.Dimension && b instanceof CartoCSS.Tree.Color) {
            if (this.op === '*' || this.op === '+') {
                temp = b;
                b = a;
                a = temp;
            } else {
                env.error({
                    name: "OperationError",
                    message: "Can't substract or divide a color from a number",
                    index: this.index
                });
            }
        }

        // Only concatenate plain strings, because this is easily
        // pre-processed
        if (a instanceof CartoCSS.Tree.Quoted && b instanceof CartoCSS.Tree.Quoted && this.op !== '+') {
            env.error({
                message: "Can't subtract, divide, or multiply strings.",
                index: this.index,
                type: 'runtime',
                filename: this.filename
            });
            return {
                is: 'undefined',
                value: 'undefined'
            };
        }

        // Fields, literals, dimensions, and quoted strings can be combined.
        if (a instanceof CartoCSS.Tree.Field || b instanceof CartoCSS.Tree.Field ||
            a instanceof CartoCSS.Tree.Literal || b instanceof CartoCSS.Tree.Literal) {
            if (a.is === 'color' || b.is === 'color') {
                env.error({
                    message: "Can't subtract, divide, or multiply colors in expressions.",
                    index: this.index,
                    type: 'runtime',
                    filename: this.filename
                });
                return {
                    is: 'undefined',
                    value: 'undefined'
                };
            } else {
                return new CartoCSS.Tree.Literal(a.ev(env).toString(true) + this.op + b.ev(env).toString(true));
            }