docs: clarify short options hopefully coming

[shadowspawn]

We do not want -foo to be the same as --foo. That much is fairly certain.

-foo is likely to be the same as -f -o -o, at least when plain flags. But nothing implemented yet, so point to issue rather than speculate.

See #2

[ljharb]

iow, -foo must be either -f -o -o or -f oo?

[shadowspawn]

Or -f -o o.

[ljharb]

oof, that sounds like a horrific result, because how would i know at a glance what it means if that were a possibility?

[shadowspawn]

This is not a common or encouraged usage. But it is a possibility.

In this scenario the person who wrote the command invocation knows that -o takes a value. They know that you may put the value directly after the short option. They know that you may combine short options. (And if they did this in a script then apparently they don't care about the readability and maintainability!)

It might look more reasonable with a progression, and one feature at a time:

start --verbose --port 80
start -v -p 80
start -v -p80
start -vp80

Real world example:

% tar -xff
tar: Error opening archive: Failed to open 'f'

[ljharb]

That combination of obscure knowledge doesn't seem worth it to me to be able to do -xff instead of being forced to add a space and a dash (-x -ff).

[ljharb]

How is -f o -o any different than -f -o o? The order shouldn't matter for this scenario, only if f or o, respectively, is declared withValue.

[bcoe]

Perhaps we should make the example is -bar the same as --bar, so there isn't confusion due to the oo.

I think in both cases it should be: -b -a -r, and -f -o -o, and the multiple os would just clobber each other.

We could eventually consider adding support for multiples so that -o, -o would be o: 2, but I think this also supports the -f, -o, -o, interpretation.

[shadowspawn]

Less issues with --bar but the key point is the answer is now "no". That is a step forward for the README!

[ljharb]

@bcoe i'm 100% fine with what you think it should be in that comment. I found "-bar could be -b a -r or -b -a r, no matter how they're configured, both to be unacceptable.

[shadowspawn]

I'll do some fresh exploration on potential -bar equivalence to -b -a r. I went deep on this a couple of years ago because of bugs reported against Commander which at the time did a blind expansion of -foo to-f -o -o, and separately requests and PR for support for -p80. So I have been here before.

[shadowspawn]

Thanks reviewers. I will merge this weekend if nothing else comes up.