# parse method

BigInt parse (String source, { int radix })

Parses `source` as a, possibly signed, integer literal and returns its value.

The `source` must be a non-empty sequence of base-`radix` digits, optionally prefixed with a minus or plus sign ('-' or '+').

The `radix` must be in the range 2..36. The digits used are first the decimal digits 0..9, and then the letters 'a'..'z' with values 10 through 35. Also accepts upper-case letters with the same values as the lower-case ones.

If no `radix` is given then it defaults to 10. In this case, the `source` digits may also start with `0x`, in which case the number is interpreted as a hexadecimal literal, which effectively means that the `0x` is ignored and the radix is instead set to 16.

For any int `n` and radix `r`, it is guaranteed that `n == int.parse(n.toRadixString(r), radix: r)`.

Throws a FormatException if the `source` is not a valid integer literal, optionally prefixed by a sign.

## Implementation

    external static BigInt parse(String source, {int radix});