The remove functions no longer return `Arc` but the core type, at the
cost of requiring `Clone`. I originally held off on this
in #3732 in the hope of gracefully transition the derive and requiring
`Clone` would have been a breaking change but when it came to #3734, I didn't
find a way to make it work without a breaking change, so I made it
opt-in. This means I can force the `Clone` requirement now.
I added the requirement for `Clone` everywhere else in the hopes that in
the future, we can drop the `Arc` without a breaking change.
When to show usage? We are currently mixed about it. For `validator`,
we didn't show it at all. Sometimes we show the used arguments and
sometimes we don't.
With `ValueParser`, I ran into the problem that we weren't showing the
used arguments like we had previously in some cases. In deciding how to
solve this, I went with the simplest route for now and removed it as the
usage likely doesn't add much context to help people solve their
problem, more so the recommendation for help. We'll see how the
feedback is on this and adjust.
For clap 3, its opt-in as a precaution against breaking
compatibility in some weird cases.
This does require the types to implement `Clone`.
Fixes#3734Fixes#3496Fixes#3589
`multicall` allows you to have one binary expose itself as multiple
programs, like busybox does. This also works well for user clap for
parsing REPLs.
Fixes#2861
In case the `ArgMatches` is cloned, this forces a constraint that the
underlying type impls `Clone` but that should be safe as we only support
`String` and `OsString`.
There are several approaches with this
- `value_parser(N..M)`: creates an i64 range
- `value_parser(value_parser!(u16).range(10..))`: creates an u16 range
that starts at 10
- `RangeI64ValueParser`: create whatever range you want
I was hoping to generalize `RangeI64ValueParser` for any source type,
not just i64, but ran into issues and decided to punt. I chose `i64` as
the source type as it seemed the most general and didn't run into
portability issues like `isize`.
This is a step towards #3199. All that is left is for the derive to use
this.
