static parseFloat(text) {
        if (text.length === 0) {
            throw new Error("Not a number: '" + text + "'");
        }
        if (text[0] === "-") {
            return -Format.parseFloat(text.substr(1));
        }
        if (text[0] === "\u221A") {
            return Math.sqrt(Format.parseFloat(text.substr(1)));
        }

        let fraction = match(UNICODE_FRACTIONS, e => e.character === text);
        if (fraction !== undefined) {
            return fraction.value;
        }

        let result = parseFloat(text);
        if (isNaN(result)) {
            throw new Error("Not a number: '" + text + "'")
        }
        return result;
    }
Parses the given text into a float. Works for text created by Format#formatFloat.
@param {!string} text
@throws
@returns {!number}