Use ArgGroup to enforce relative positioning

[matu3ba]

As far as I understand it, there is no option to restrict the relative positioning of arguments or the documentation may be unclear to me or missing.

I would like to have
program [ArgGroup1] [ArgGroup2] [ArgGroup3],

where after an occurence of any element of ArgGroup2 no occurence of any element in ArgGroup1 and after an occurence of any element of ArgGroup3 no occurence of any element in ArgGroup2 and 1 happens.

ArgGroup1 could be indicated by index(1), ArgGroup2 by index(2), etc.

If one would implement this in loop with a match, this would boil down to

gindex = 0
while arg in cliargs {
    match arg {
        "--version" | "-v" => {
            if gindex > ArgGroupIndex1 { eprintln!("wrong group position") }
            else { dostuff(); gindex = ArgGroupIndex1; }
        }
        ...
    }
}

In my use case I need
program [FLAGS] [OPTIONS] [args] with flags and options being limited in numbers and arguments not. args can also have arbitrary many items.

Am I wrong on this?

[pksunkara]

If ArgGroup1 contains a and b, ArgGroup2 contains c and d. Set the arg groups as required and then index all the args in increasing order (a=1, b=2, c=3, d=4). That should give you what you want.

[pksunkara]

Try with clap master. Also you shouldn't have short/long with index.

[matu3ba]

Why is it then not a compile time bug to combine short, long and an index?

Does this mean that I can not restrict the positioning of flags and options?

I tried master, but the indexing (as you warned) broke the program input completely.

[pksunkara]

It is a compile bug in v3 but not v2. And yes, you can not restrict the positioning of flags and options. It is a major CLI convention.

[matu3ba]

Thanks. This sounds like a terrible old standard, when you can programmatically reorder input options for better readability.

[pksunkara]

It's old but gold standard. It has a better user experience where people don't have to care about flags and options position and wont' get frustrated.