This is a bit ugly and requires that we put our where-clauses in
parentheses because the macro_rules parser sucks, but it allows us to
move the blanket-impls on NumOpResult into the macro.
This commit moves one instance and updates the macro; the next commits
will change the rest.
Looks like a large diff but if you run
git show --color-moved-ws=allow-indentation-change
you will see that it's 100% moves (though moves of code into the
reference macro). May be easier to just look at src/amount/result.rs
after this; it's pretty short now.
The next commit changes a lot of code, but almost entirely by moving and
indenting it. We try to do the moves here ahead of time, so it the diff
for the next commit will be just deletions and indentations.
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.
The `NumOpResult` type is way more ergonomic to use if it derives
`Copy`. This restricts the `NumOpResult` to being `Copy` as well.
This does restrict what we can include in the error type in the future.
Derive Copy for `NumOpResult` and `NumOpResult`.
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.