Available on crate feature
unstable-doc
only.Expand description
Documentation: Feature Flags
Available compile-time feature flags
Default Features
- std: Not Currently Used. Placeholder for supporting
no_std
environments in a backwards compatible manner. - color: Turns on colored error messages.
- suggestions: Turns on the
Did you mean '--myoption'?
feature for when users make typos.
Optional features
- deprecated: Guided experience to prepare for next breaking release (at different stages of development, this may become default)
- derive: Enables the custom derive (i.e.
#[derive(Parser)]
). Without this you must use one of the other methods of creating aclap
CLI listed above. - cargo: Turns on macros that read values from
CARGO_*
environment variables. - env: Turns on the usage of environment variables during parsing.
- regex: Enables regex validators.
- unicode: Turns on support for unicode characters (including emoji) in arguments and help messages.
- wrap_help: Turns on the help text wrapping feature, based on the terminal size.
Experimental features
Warning: These may contain breaking changes between minor releases.
- unstable-replace: Enable
Command::replace
- unstable-grouped: Enable
ArgMatches::grouped_values_of
- unstable-v4: Preview features which will be stable on the v4.0 release