Edit subcommand markers

[mondeja]

Please complete the following tasks

• I have searched the discussions
• I have searched the open and rejected issues

Clap Version

4.5.20

Describe your use case

Currently, subcommand markers are generated as <> for required subcommands or [] for optional ones.

I would like to edit them. This would make transitions from other tools or rewritings much more easy.

For example, in Python by default are presented as {cmd1,cmd2...}, see https://docs.python.org/es/3/library/argparse.html#argparse.ArgumentParser.add_subparsers at:

metavar - string presenting available subcommands in help; by default it is None and presents subcommands in form {cmd1, cmd2, ..}

Describe the solution you'd like

I would like a to call a method like subcommand_markers("{", "}"). For example:

Command::new("foo")
    .subcommand_value_name("run,install")
    .subcommand_markers("{", "}")

Running foo --help:

Usage: foo {run,install}

...

Alternatives, if applicable

No response

Additional Context

No response

[epage]

In clap, we try to balance a couple of factors

• Encourage people towards best / common practices while this goes off into less common practices
• Be careful of our built-in configurability because extending the API comes at the cost of build-times / binary size and the larger the API is, the harder it is for users to find features, making new features reduce the value of every feature of clap

We are interested in decoupling formatting and maybe that would be a way for you to provide a custom skin to handle these different formats. We are tracking this in #2914 and closing in favor of that.