Introduce `apply` as alternative to `:=`

[lolgab]

Laminar introduced the convention (I'm not sure if this was already available before somewhere else) to replace the attribute := value syntax with attribute(value). I find this syntax much easier to use, and it would be nice if Scalatags supported it.

[lihaoyi]

TBH I've thought about this before. It would be a major syntactic change, but the change would only by skin-deep. I'm curious what other people think about it? This is definitely a preference thing, and I'd be happy to go along with whatever the overall consensus is.

@lolgab perhaps you could flesh out the PR description a bit: explain why you're doing this, what the pros and cons are, provide a few more examples, etc.. Then I'll see if I can get folks to look at this PR to see what they think in aggregate?

[raquo]

My two cents:

In Laminar we use := throughout documentation because that method name is easier to refer to in writing (if we're talking about apply, we need to clarify which apply, but there is only one :=), and it's easier for people learning the library to go-to-definition of this method in their IDE to see what it's doing (in contrast, the apply method name does not actually appear in your code if you use it, so it's not obvious how you can get to its method definition in the IDE).

In Laminar docs there's a short section that recommends that people use apply, but otherwise it's left up to users. I think it's good to give users the option, considering how dramatic the visual change is, and how cheap it is to implement.

Personally I vastly prefer typing shift+9 to space-shift-colon-equals-space, and I like the resulting clean look too.

[raquo]

Oh, one other aspect of using apply syntax is that usages of user-defined helpers which return modifiers, such as myFontVariant(brand.darkThemed), look more first-class, similar to library-built-ins like key(attr). This gives a more uniform look. Conversely, when you use the := method for built-ins, user-defined helpers like this stand out visually (unless users take the effort to define classes / extension methods to match the := syntax, which is annoying).

I'm not saying which side of this aspect is the winner, I'm not sure myself, just something I've noticed in a similar context of Laminar's --> <-- methods (which have no apply equivalent, unlike :=... maybe they should, but it starts feeling too magicky at this point).

[seoethereal]

Seems nice but please do not deprecate the := yet!

[Bathtor]

Seems nice but please do not deprecate the := yet!

Please don't deprecate := ever.

The apply syntax is nice, and I'm happy for people to use it who like that. But for myself, I got enough parenthesis nesting in my code without it. Any more and I'll feel like I'm writing Lisp :D