Clarify in docs that zero is not considered a positive-int

[bdsl]

I wasn't sure from reading the docs whether or not Psalm consider zero to be positive.

[AndrolGenhald]

Idk, "positive" has always had a clear well established meaning to me 🤷

If we're going to bother changing it though, I would say:

positive-int only allows positive integers (equivalent to int<1, max>)

which provides the same information but also points people to the newer int range feature which is much more useful.

Speaking of, int ranges should probably be documented there as well, and we should make sure there aren't any other scalar types missing documentation.

[bdsl]

I like your version @AndrolGenhald. The way I was taught in school, 'positive' means >= 0, and 'strictly positive' means > 0. But in informal usages positive could mean either one.

[bdsl]

Wikipedia gives both definitions of positive: https://en.wikipedia.org/wiki/Sign_(mathematics)#Terminology_for_signs

[AndrolGenhald]

Wow, I never realized there was differing terminology there, I've only ever known [non-]positive and [non-]negative!

[bdsl]

btw the type I was actually looking for was the int<0,max> one. Probably a lot of use cases for that, counts of things, prices etc that can be zero or positive. Maybe worth a separate PR to create a non-negative-int type as an alias of that.

Probably not enough use cases for negative-int or non-positive-int to justify them going in, unless it's just to make the system more symmetrical.

[bdsl]

at least with integers there's only one zero! Float has +0 and -0 of course.

[AndrolGenhald]

Personally I've just moved to using int ranges everywhere, it's shorter and easier to understand. Before int ranges were introduced there were a lot of 0|positive-int around which also works fine, so I don't think there's really much need for new types here.

Edit: @orklah mentions here that apparently PHPStan supports negative-int, so in that case it might be worth adding just for feature parity, however unnecessary I think it is. There's also #7769 which was closed as soon as OP learned about int ranges (which should be documented better... I opened #8061 to make sure it doesn't get forgotten).

[AndrolGenhald]

Slight nitpick: use backticks for int<1, max>?

[bdsl]

Done, thanks.

[orklah]

Oh, I thought I already added negative-int but I guess not. It should be easy to do if someone wants to add that

[orklah]

Thanks!