Do not require angle brackets in argument

[Minoru]

From ryanartecona's comment on issue #4:

Having to specify the angle brackets in an argument lookup does feel like a mistake, though.

Thought so, too! That turned out to be trivial to fix.

If you merge this, I can open an issue so you don't forget to make a new release once you get back from your vacation. Have a good time!

[ryanartecona]

Ah! Great catch. Thanks for the PR, and apologies for having to dig through the source of my first/only real Haskell project! :P

I think, technically, this fix results in arguments with the same name but differing style, e.g. ARG and <ARG>, clashing. Though since ARG and <arg> would coexist fine, I am good with this. Both cases are probably smells for a bad CLI anyway.

Will make a new release once I can test and verify. A new issue would be appreciated. :)

[Minoru]

My pleasure! I don't know if the merit is Haskell's or yours, but the place I needed to tweak was really easy to find - just start with a function from public API and then grep a bit to find where pDocopt is defined.

I think, technically, this fix results in arguments with the same name but differing style, e.g. ARG and <ARG>, clashing.

I don't view that as a problem, because I don't think we need to distinguish between the two at all. To me, it's really a matter of style: you either choose one or another, and stick to it.

Both cases are probably smells for a bad CLI anyway.

I'm just curious: why do you think so?

[ryanartecona]

For the sake of tying off loose ends:

I'm just curious: why do you think so?

By "bad CLI", I really meant "an inconsistent usage page". A usage page which either uses both ARG and <ARG> or both ARG and <arg> style of positional arguments could just as easily choose one of those styles to use throughout that usage page.

I personally prefer the <brackets> because it reads less ambiguously to me, but I know some others are more accustomed to UPCASE. Either way, there's no reason to mix them in these same usage page, so we shouldn't worry about supporting that in docopt.

[Minoru]

Oh, I just misunderstood the meaning of "both cases" back then — I read it as if you meant "both arg and <arg> smell of bad CLI". Consider that particular loose end a false one :)