docopt.cpp

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Fiven the following usage string:

Usage:
  vrplayer-openvr [--option VALUE]

Options:
  --option VALUE  Set of options (first|second|third) [default: first]

Is it possible to validate a set of options (see the values in the parenthesis.

Could it be written also as:

  --option VALUE  Set of options [values: first|second|third, default: first]

If not possible, then its a feature request.

What is expected is that the parser also restrict the used option value (and throws if invalid). In the my example, I have a pipe list, but actually could it be a regex?

Any comment on this?

Related: https://github.com/docopt/docopt/issues/45

No, the syntax doesn't have any way to do this .. it would be up to you to provide that kind of validation when you look at the values you get. I think trying to adjust the syntax would be tricky to do.

What about syntax proposed above by @isometriq ? --option VALUE Description… [values: first|second|third, default: first]

Looking in the man pages for git, I think a better syntax would be:

--diff-algorithm={patience|minimal|histogram|myers}

I think this could be a nice addition, however this library tries to conform to the "standard" put forth by the peer project and original "Docopt" in Python. So before I could adopt this, it would need to be proposed and implemented in the original.