The CSSWG (CSS Working Group of workers) is at existing debating what to title a conditional construction, and it’s roughly charming.  There are a quantity of sturdy opinions, and I’m now not definite how a quantity of them are weakly held.

Boiled down to the bare bones, the muse is to scheme shut the conditional structures CSS already has, fancy @supports and @media, and allow extra generic conditionals that combine and presents a boost to what these structures manufacture imaginable.  To have interaction a frequent example, this:

@supports (conceal: grid) {
	@media (min-width: 33em) {
		…
	}
}

…would change into something fancy this:

@conditional supports(conceal: grid) and media(min-width: 33em) {
	…
}

This might perchance additionally be extended to permit for alternates, something fancy:

@conditional supports(conceal: grid) and media(min-width: 33em) {
	…
} @in any other case {
	…
}

Except no one wants to want to form @conditional and @in any other case, so the WG went searching for shorter names.

The Sass-savvy amongst you are doubtlessly leaping up and down honest now, shouting “We contain that! We contain that already! Edifying name them @if and @else and in a roundabout design acquire on our stage!”  And yes, you attain contain that already: Sass uses precisely these keywords.  There are some minor syntactic variations (Sass doesn’t require parentheses spherical the conditional assessments, for instance) and it’s now not wonderful whether or now not CSS would allow trying out of variable values the manner Sass does, however they’re very identical.

And that’s a remark, due to if CSS starts the expend of @if and @else, there might be the aptitude for syntactic prepare wrecks.  Whenever you happen to’re writing with Sass, how will it notify the variation between its @if and the CSS @if?  Will you be with no wreck in sight barred from the expend of CSS conditionals in Sass, if that’s what goes into CSS?  Or will Sass be forced to rename these conditionals to something else, in impart to steer wonderful of clashing — and if so, how powerful upheaval will that manufacture for Sass authors?

The present proposal, as I write this, is to make expend of @when and @else in CSS True.  Thus, something fancy:

@when supports(conceal: grid) and media(min-width: 33em) {
	…
} @else {
	…
}

Even supposing there might be overlap with @else, curiously starting the total construction with @when would allow Sass to notify the variation.  In recount that will presumably presumably sidestep clashing with Sass.

But can contain to collected the CSS WG even care that a third-occasion code unsuitable’s syntax gets trampled on by CSS syntax?  I imagine Sass authors would negate, “Uh, hell yeah they want to collected”, however does that outweigh the aptitude studying hurdle of your complete non-Sass authors, every now and over the next couple of decades, studying that @when doesn’t even contain temporal meaning and is completely an alias for the extra recognizable if statement?

Because while it’s correct that some programming languages contain a when conditional construction (kOS being the one I’ve primitive most currently), they in total additionally contain an if construction, and the two as soon as in a while mean assorted issues.  There is a gape held by some that the expend of the pricetag when after we in actuality mean if is a mistake, one which will stand out as a uncommon alternative and a fabricate blunder, 10 years as a consequence of this truth, and can contain to collected manufacture a cognitive snag in the formulation of studying CSS.  Others help the gape that when is a lovely frequent programming time period, it’s as soon as in a while synonymous with if, every language has quirks that original newbies have to be taught, and it’s price fending off a conflict with tools and authors that already exist.

Whenever you happen to question me, every views are correct, and that’s the exact remark.  I imagine a quantity of the participants in the discussion, although their robust opinions are strongly held, can now not lower than ogle the put the alternative gape is rooted, and sympathize with it.  And it’s very doubtless the case that although Sass and other tools didn’t exist, the WG would collected be having the identical debate, due to every phrases work in context.  I believe if would contain obtained by now, however who knows?  Presumably now not.  There contain been longer debates over less traditional ideas over the years.

A form of my expert existence has been spent explaining CSS to americans original to it, so as that will presumably presumably be why I for my part lean in direction of @if over @when.  It’s reasonably more uncomplicated to label, it appears to be extra acquainted to anyone who’s done programming at almost about any stage, and semantically it makes reasonably extra sense to me.  It’s additionally correct that I approach from a trouble of now not having to danger about Sass altering on me, due to I’ve on the total never primitive it (or any other CSS pre-processor, for that matter) and I don’t want to realize the heavy lifting of rewriting Sass to deal with this.  So, easy for me to screech!

That acknowledged, I even contain an instinctive distrust of arguments by majority.  Yes, the sequence of Sass builders who’d want to adapt Sass to @if in CSS True is vanishingly small compared to the inhabitants of present and future CSS authors, and the sequence of Sass authors is doubtless powerful smaller than the sequence of total CSS authors.  That doesn’t automatically mean they want to be discounted. It’s lawful to help CSS as future-proof as imaginable, however it completely can contain to collected additionally be saved as present-proof as imaginable.

The rub comes in with “as imaginable”, although.  This isn’t a danger the put all issues are imaginable. Something’s going to present, and there will doubtless be a personnel of parents ill-served by the final end result.  Will it is Sass authors?  Future CSS newbies?  One more personnel?  Each person?  We’ll ogle!