clap/clap_derive/examples/README.md
2020-01-18 17:40:07 +05:30

1.8 KiB

Collection of examples "how to use clap_derive"

Help on the bottom

How to append a postscript to the help message generated.

At least N

How to require presence of at least N values, like val1 val2 ... valN ... valM.

Basic

A basic example how to use clap_derive.

Deny missing docs

This is not an example but a test, it should be moved to tests folder as soon as this is fixed (if ever).

Doc comments

How to use doc comments in place of help/long_help.

Enums as arguments

How to use arg_enum! with clap_derive.

Arguments of subcommands in separate struct

How to extract subcommands' args into external structs.

Environment variables

How to use environment variable fallback an how it interacts with default_value.

Advanced

Somewhat complex example of usage of clap_derive.

Flatten

How to use #[clap(flatten)]

Git

Pseudo-git example, shows how to use subcommands and how to document them.

Groups

Using clap::Arg::group with clap.

key=value pairs

How to parse key=value pairs.

--no-* flags

How to add no-thing flag which is true by default and false if passed.

No version

How to completely remove version.

Rename all

How #[clap(rename_all)] works.

Skip

How to use #[clap(skip)].

Aliases

How to use aliases

true or false

How to express ""true" or "false" argument.