Immutability of Int is broken by BigInt() method

[cloudgerman]

Hi, First of all, great work! It is a pleasure working the library. I realized that Int's interface is immutable, except for the following method (big.Int is mutable):

// BigInt returns the value as a big.Int. // The returned variable must not be modified by the client. func (i Int) BigInt() *big.Int { ... }

Is that for a reason? I see the method is used internally in several places. I would imagine it is better to split it in 2:

• BigInt() -> public method, returns a copy of the BigInt to maintain the immutability properties
• bigInt() -> internal, returning directly the reference to the big.Int. Not sure if the naming I propose would be best, other ideas could be ptrInt(), internalBigInt(), bint(), ...

If this is something that would be approved, I can work on the change and send a pull request.

Best, Germán

[alandonovan]

Fair enough, let's make BigInt return a copy, and bigInt avoid the copy if possible. Thanks.