6244cb75fa Introduce monadic AmountOpResult (Tobin C. Harding)
Pull request description:
We would like to return an error when doing math ops on amount types. We cannot however use the stdlib `Result` or `Option` because we want to implement ops on the result type.
Add an `NumOpResult` type. Return this type from all math operations on `Amount` and `SignedAmount`.
Implement `core::iter::Sum` for the new type to allow summing iterators of amounts.
Note please this removes `AddAssign` impls for amount types.
ACKs for top commit:
apoelstra:
ACK 6244cb75faf62aed4b47d63a59d14cb766e4e7a8; successfully ran local tests; let's do it -- but definitely want the followup issues addressed
Kixunil:
ACK 6244cb75fa
Tree-SHA512: 7a105acb1aa492ab3e97d94ae182ac4c30a364edd183f71cc320cf80d85060049e8caf1e5736ef6d1af32f39c3376f21382afe35ac65ea1b8c15130c622d9d64