limit possible values for parameters + required vs optional parameters

[jeroenjacobs79]

Hi,

I'm going to be honest, I'm a newbie at Go development and I mostly used Python + its argparse module for my commandline tools.

I've been going through the documentation, but I'm struggling with a few concepts:

• How can I limit a certain commandline parameter to certain values? Eg: I have a commandline parameter "--type" which can only accept the following values: picture,sound or video. so "--type=video" would be valid, but "--type=program" will not. Is there a way to specify these constraints? Python's argparse module can solve this with the "choices" option.

• How can I dictate a certain commandline should always be specified? Eg: "--type" should always be specified, with a value.

[jszwedko]

Hi @jeroenjacobs1205!

• Restricting flag options is not directly supported by this library currently, but is achievable via the exposed GenericFlag interface (declaring a struct implementing the GenericFlag interface that validates the value during the .Set() operation).
• Required flags have been the topic of much discussion, but are also not currently directly supported by the library (see Required Flags #85 for more) . You can achieve similar results by validating that the flags are set after parsing using Context.IsSet..

Thank you for your interest! Just let me know if any of this is unclear.

I'll mark this as an enhancement with regard to the flag value restriction.

[coilysiren]

Given that this is from last year, I think I'm comfortable closing it 🙂 feel free to re-open / open a new issue / comment in support if there's still interest here!

[abdennour]

/reopen /open /re-open

[rliebz]

@abdennour I re-opened and pinned #1154 (so it won't go stale), let me know if there's anything from this issue that warrants re-opening in addition.

[abdennour]

Thank you @rliebz ! should this answer #602 (comment) cover this issue ?

[rliebz]

I think so, seems pretty straightforward.