method

parse

Source

/**
 * Parse [source] as an double literal and return its value.
 *
 * Accepts an optional sign (`+` or `-`) followed by either the characters
 * "Infinity", the characters "NaN" or a floating-point representation.
 * A floating-point representation is composed of a mantissa and an optional
 * exponent part. The mantissa is either a decimal point (`.`) followed by a
 * sequence of (decimal) digits, or a sequence of digits
 * optionally followed by a decimal point and optionally more digits. The
 * (optional) exponent part consists of the character "e" or "E", an optional
 * sign, and one or more digits.
 *
 * Leading and trailing whitespace is ignored.
 *
 * If the [source] is not a valid double literal, the [onError]
 * is called with the [source] as argument, and its return value is
 * used instead. If no `onError` is provided, a [FormatException]
 * is thrown instead.
 *
 * The [onError] function is only invoked if [source] is a [String] with an
 * invalid format. It is not invoked if the [source] is invalid for some
 * other reason, for example by being `null`.
 *
 * Examples of accepted strings:
 *
 *     "3.14"
 *     "  3.14 \xA0"
 *     "0."
 *     ".0"
 *     "-1.e3"
 *     "1234E+7"
 *     "+.12e-9"
 *     "-NaN"
 */
external static double parse(String source,
                             [double onError(String source)]);