This has been implemented for 3 years without much traction for
finishing it up.
The subcommand use case can be worked around by creating `Command`s that
just include the relevant logic, very similar to the default subcommand
examples in `git` / `git-derive`.
Using this for flags is covered by #4793.
Without `unstable-replace` being enabled, this still cut 5 KiB from
`cargo bloat --release --example git`.
Closes#2836Closes#2011
This let's you get an arguments values, grouped by the occurrence of the
argument.
Note: this does not stablize derive support. That requires a blocking
change and can be enabled via `unstable-v5` flag. See #4626 for an
exploration of how we can make this easier in the future.
Fixes#2924
This is a cheap pass at creating this to allow cutting out the cost of
rich error information / programmatic error information.
This cuts about 20 KiB off of the binary.
There is more we could cut out, like collecting of used arguments for
the usage, but I want to keep the conditionals simple.
Originally, clap carried a lifetime parameter. When moving away from
that, we took the approach that dynamically generated strings are always
supported and `&'static str` was just an optimization.
The problem is the code size increase from this is dramatic. So we're
taking the opposite approach and making dynamic formatting opt-in under
the `string` feature flag. When deciding on an implementation, I
favored the faster one rather than the one with smaller code size since
small code size can be gotten through other means.
Before: 567.2 KiB, 15.975 µs
After: 541.1 KiB, 9.7855 µs
With `string`: 576.6 KiB, 13.016 µs
`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
