Some documentation/definition lacks

[ZeroAurora]

Here I'll lay down some incomplete documentation areas I found while wandering through v's websites (for a note to maintainers and perhaps myself)

• templating in veb (vweb has complete templating docs, but not veb)
• macros (no they aren't but they really look like it) comptime
  • (@['/'] and $veb.html(), vweb is using for a long time but not documented, looking like procedual and declaritive)
  • and other comptime features (how does sql db {} even works!! it just looks like a keyword)
• environment variables recognized by compilers (random link)
  • I've always wanted to disable tcc usage - I know I can define a envvar for that, please doc
• deprecated vlibs list
• ...

[JalonSolov]

V doesn't do macros, and neither do veb/vweb. What they do has is templates. As for how sql db works, it is "compiler magic".

You can't disable tcc usage, but you can tell V not to use it by setting VFLAGS env var. Putting V command line options in there will cause V to always apply them along with whatever you type on the command line. So, for example, if you want V to always use gcc instead of tcc, just set VFLAGS="-cc gcc".

Why you would want to do that, when tcc is so much faster for prototyping, I don't know. But you are free to do it if you wish.

Using -prod will also make V skip using tcc, and instead use gcc/clang/msvc, as well as enabling optimizations. Much slower than just -cc gcc, but the code will be optimized, and usually smaller/faster than without.

You are correct that all the env vars aren't documented in one place, and there is no separate "deprecated" list, although I don't know why one would be needed.

[ZeroAurora]

"marcos" I'm mentioning is things like @['/'] and $veb.html(). I believe that they are built by some kind of metaprogramming. And for sql db, if it's driven by compiler magics, I think sql should be a keyword.

I've opened some discussions about V's tcc usage (on reproducibility). I feel unsure if something is broken by the patched compiler.

For the deprecated list: V is growing fast and I think there should be some places for people to track API changes. CHANGELOG.md is not sufficient especially for people who track the latest version on master branch.

[ZeroAurora]

I was considering the undocumented attributes as a kind of macro... I apologize for that.

[jorgeluismireles]

Attributes seems something obscure, but are in members of V objects that both lib and apps programmers can define and read, and even write like when users's enum code is parsed by the compiler to autogenerated more V code reading attrs. For example, you can define and read attributes for your code:

struct Struct {
	elem string @[alpha; beta]
}

@[gamma;delta]
@[epsilon:0]
fn (s Struct) method() {
	
}

fn main() {
	s := Struct{}
	$for e in s.fields {
		println('field:${e.name} attrs:${e.attrs}')
	}
	$for m in s.methods {
		println('method:${m.name} attrs:${m.attrs}')
	}
}

field:elem attrs:['alpha', 'beta']
method:method attrs:['gamma', 'delta', 'epsilon: 0']

[ZeroAurora]

I found $veb.html() in this file: https://github.com/vlang/v/blob/master/vlib/v/parser/comptime.v
And sql: https://github.com/vlang/v/blob/master/vlib/v/parser/orm.v

They are both tightly integrated inside the compiler. I don't really think it's a good design - library-specific comptime features should be decoupled - but that would fit in another discussion.

And sql is actually treated like a keyword... I'm worried about whether we are adding more domain-specific keywords to the language. V is not a DSL.

But again that fits in another discussion. We can have some little chat here and if you don't mind my noise in discussion area I'll open another ones.

[jorgeluismireles]

I would like to discuss the comptime problem further. Maybe I would open another discussion for that.

Yes, and read old discussions, there is a lot of these.

[JalonSolov]

Umm... comptime is just shorthand for compile-time... how else would you implement compile-time features other than in the compiler?

[ZeroAurora]

Umm... comptime is just shorthand for compile-time... how else would you implement compile-time features other than in the compiler?

macros are a way to accomplish this, but we also have zig as an example of macro-less languages

[JalonSolov]

V is macro-less by design, so that will never be a solution for V.

[ZeroAurora]

Yes, but we can do current comptime features better. (say, we already have $if and $for, and we can expand that further.)