This both distances itself from our 'require' terminology and aligns
itself with `Option::expect`, making it more likely for people to guess
the intended behavior.
This makes it easier for us to compose. Before, we had to infer things
like "bold" based on the color. Now we just say "error" and get all of
the formatting specific to that.
Too many times people have to disable default features. Let's try to
have a more minimal out of box experience.
- `derive`: people are already used to adding this feature for serde
- `cargo`: not needed for derive
- `env`: most probably don't use this
- `unicode`: most CLIs are probably ASCII. We should do a debug warn
about this though
BREAKING CHANGE: `derive`, `cargo`, `env`, and `unicode` are no longer
on by default.
This ports our example testing over to [trycmd](https://docs.rs/) so
we can:
- More thoroughly test our examples
- Provide always-up-to-date example usage
The old way of testing automatically picked up examples. This new way
requires we have a `.md` file that uses the example in some way.
Notes:
- Moved overall example description to the `.md` file
- I added cross-linking between related examples
- `14_groups` had a redundant paragraph (twice talked about "one and
only one"
This is intended to replace the runtime usage parser and is not meant to
be a complete API in of itself, like `clap_app!`. What is in scope is
everything that visually makes sense as in a usage string (see
[docopt](http://docopt.org/) for inspiration). General setting of
attributes is out of scope.
This deviates from both `clap_app` and the runtime usage parser
- `clap_app` supported multiple values but has a bug because we made
`Arg::value_name` non-appending, so we aren't supporting this yet
- We do not yet support optional flags that take a value
- In both, `...` is multiple occurrences and values while its only
multiple occurrences for us
- We explicitly support optional values for flags
- Unlike `clap_app`, our name is optional
- Unlike runtime usage parser, our name syntax is simpler
- Unlike runtime usage parser, our name syntax does not allow modifiers
Its more limited than I would like. Hopefully some people better with
macros can expand the feature set and turn more runtime errors into
compile-time errors.
This is to prepare for deprecating the runtime usage parser (#8).
Since usage parser and yaml are on the way to being deprecated (#8, #9),
doing a rename also seems excessive, so rolling it back.
Past relevant PRs:
- clap-rs/clap#1157
- clap-rs/clap#1257
This reverts commits 24cb8b1..d0abb37 from clap-rs/clap#1840
This is part of #16. clap-rs/clap#1840 wasn't the right call but we
don't have time to make the decision now, so instead of having one
option and changing it in 4.0, this reverts back to clap2 behavior.
