add explanatory comments to _zend_op

[kaja47]

No description provided.

[krakjoe]

I question the explanatory powers of such comments: I'm not really for making these kinds of changes, I'd rather look at a clean typedef.

[kaja47]

Then do it, because I do not feel confident enough to make these kind of changed in the very hearth of PHP. But for me, as a some rando, PHP code is by its total lack of any meaningful documentation utterly incomprehensible and anything, literally any faint glimmer of guiding light like this saying what values a variable can take and what it means, would be greatly appreciated.

[krakjoe]

If we added these kinds of comments everywhere, we would still not have meaningful documentation, there would just be comments everywhere and it would make the actual code harder to read.

[nikic]

This looks fairly harmless to me. I don't think we can use typedefs here, because we need precisely controlled layout, and C does not have enum Foo : uint8_t support like in C++.

[krakjoe]

I wasn't suggesting we use typedefs, I was referring to the fact that structs and typedefs are easier to read when they are not littered with comments.

I still don't see the point in this kind of change.