This macro can generally handle a lot of different cases where we
implement "the same trait but on references". We introduce it here and
use it in two places. We will use it in many more, but I wanted to make
the diff small on this commit, which introduces the actual macro code
and might take a bit of reading to understand.
You may want to use --color-moved-ws=allow-indentation-change to review
this, and the next commit.
The next set of changes will mechanically delete other macros that are
made redundant by this.
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 `AmountOpResult` 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 - somewhat ugly to use, see tests for example usage.
Add macros for implementing `ops::Add` and `ops::Sub` for various
combinations of references. Use the macro in `fee_rate`.
These are internal macros so no need to protect `core` using
`$crate::_export::_core`.
Andrew Poelstra
Tobin C. Harding
Fmt Bot