clap/examples/cargo-example.md
Ed Page eda0ca54c1 fix(parser): Simplify the common getter API
Clap has focused on reporting development errors through assertions
rather than mixing user errors with development errors.  Sometimes,
developers need to handle things more flexibly so included in #3732 was
the reporting of value accessor failures as internal errors with a
distinct type.  I've been going back and forth on whether the extra
error pessimises the usability in the common case vs dealing with the
proliferation of different function combinations.  In working on
deprecating the `value_of` functions, I decided that it was going to be
worth duplicating so long as we can keep the documentation focused.
2022-05-25 10:50:42 -05:00

45 lines
1.1 KiB
Markdown

*Jump to [source](cargo-example.rs)*
For more on creating a custom subcommand, see [the cargo
book](https://doc.rust-lang.org/cargo/reference/external-tools.html#custom-subcommands).
The crate [`clap-cargo`](https://github.com/crate-ci/clap-cargo) can help in
mimicking cargo's interface.
The help looks like:
```console
$ cargo-example --help
cargo
USAGE:
cargo <SUBCOMMAND>
OPTIONS:
-h, --help Print help information
SUBCOMMANDS:
example A simple to use, efficient, and full-featured Command Line Argument Parser
help Print this message or the help of the given subcommand(s)
$ cargo-example example --help
cargo-example [..]
A simple to use, efficient, and full-featured Command Line Argument Parser
USAGE:
cargo example [OPTIONS]
OPTIONS:
-h, --help Print help information
--manifest-path <PATH>
-V, --version Print version information
```
Then to directly invoke the command, run:
```console
$ cargo-example example
None
$ cargo-example example --manifest-path Cargo.toml
Some("Cargo.toml")
```