Bring back possible_values (because ValueEnum does not fit everything)

[KSXGitHub]

Please complete the following tasks

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

Clap Version

4.0.26

Describe your use case

There are cases where I want to only limit user choices between strings. The behavior of the program remain exactly the same (i.e. no branches related to the user choice). For example: Choosing a weekday only to be printed out, choosing a profile between "release" and "debug" only to infer the binary path, etc.

In such cases, an enum (that derives ValueEnum) would be inconvenient since it requires me to write match to convert every single enum variant to corresponding strings.

Describe the solution you'd like

Bring back possible_values or something similar.

Alternatives, if applicable

Derive strum on the value enum. However, this method is not optimal as the resulting program still parse a string into a value enum only to convert it back to the original string.

Use value_parser = [PossibleValue::new("..."), ...] but this is unwieldy and cumbersome, especially when written in derive code.

Additional Context

I exclusively use #[derive(clap::Parser)]. I've never use the args builder directly.

[epage]

Use value_parser = [PossibleValue::new("..."), ...] but this is unwieldy and cumbersome, especially when written in derive code.

You can also do value_parser = ["always", "auto", "never"]) as shown in the (builder) example for Arg::value_parser

[KSXGitHub]

@epage I apologize, the fault lies with me for not reading the documentation carefully. I searched for the term "possible" on the docs.rs page for clap and find only the PossibleValue struct. The example for PossibleValue does not includes this convenient shorthand. May I request adding this shorthand to the code examples for PossibleValue?

[timvisee]

@epage

.value_parser(["always", "auto", "never"]) only seems to accept a list as array.

It doesn't seem to be possible to pass a runtime slice or Vec holding strings into there, or am I missing something?