zkmon 5 hours ago

Give it enough time, every declarative language becomes a programming language. This is happening with all config files, markup languages, data formats.

The distinction between code, config and data is being erased. Everything is a soup now. Data is application, configuration is code. Code is an intermediate, volatile thing that is generated on the fly and executed in the temporary lambda containers.

  • Galanwe 4 hours ago

    This is so true, I have seen it happen with so many projects. It always starts with a cute declarative DSL, and inevitably imperative / flow control structures emerge, at which point you wonder why they didn't use a real programming language in the first place and save you the hassle or learning a half baked imperative DSL.

    - Puppet

    - CMake

    - Terraform

    - ...

    All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.

    • Derbasti 4 hours ago

      - Visual Studio project files are XML files that are interpreted line by line, and can contain variables, branches, and loops. Hell on earth.

      • spooky_deep 2 hours ago

        Horrible. Would’ve been much nicer if they’d reached for Scheme.

        • debugnik 2 hours ago

          You say that, but people in OCaml keep bemoaning the use of mostly declarative s-expressions in the Dune build system. Imagine the reaction if MSBuild used an actual Scheme.

      • Xelbair 3 hours ago

        what's even worse that schema uses extremely generic types with attributes denoting actual type.

        Makes reading it even harder, and any possible constraints due to type safety go out of the window, so we get worst of both worlds.

    • spooky_deep 2 hours ago

      CMake was never declarative AFAIK?

      CMake today is effectively an eso-lang / Turing tarpit with some “modern” declarative conventions that people try to push.

      • ahartmetz 12 minutes ago

        "Modern CMake" is more about scoping all properties to the targets that they belong to (including stuff like what you also need to link against if you link against target foo) than about language features. The CMake language hasn't changed much except correcting some early weirdness about "if" and the addition of generator expressions, which are fortunately not often needed.

  • lucideer 2 hours ago

    You have to give it to CSS, it's held out for a lot longer than most.

    • rebane2001 30 minutes ago

      not as much as you would think, the if statements don't really affect the css crimes scene because pretty much everything was already possible before

  • holri 4 hours ago

    > The distinction between code, config and data is being erased.

    This distinction never existed in LISP. Greenspun's tenth rule in action.

  • thwarted 5 hours ago

    We can blame von Neumann (et al) and his infernal architecture, where memory stores both instructions and data.

    • josefx 4 hours ago

      You can blame whoever invented the word "if", as soon as you can branch based on data you can just write an interpreter that turns data into instructions, no matter the architecture.

      • amelius 3 hours ago

        You need more than if for Turing completeness though.

        • alexdns 3 hours ago

          Correct. You need at least 2 ifs.

          • spooky_deep 2 hours ago

            You need unbounded recursion no?

            • dotancohen an hour ago

              That's actually what two ifs could be.

    • account42 4 hours ago

      Not really, most of these configuration as code systems are not executed directly on the CPU but rather interpreted in which case a separate data-only memory would not stop anyone.

    • tovej 4 hours ago

      von Neumann did not invent the von Neumann architecture. Not even a little bit.

      If you want to reason that the hardware is at fault, you should be blaming the Eckert-Mauchley architecture.

  • noosphr an hour ago

    Those who don't use lisp are destined to re-invent it - poorly.

  • skywhopper 17 minutes ago

    “Now”? This has always been the case.

  • mseepgood 3 hours ago

    So why do people still design declarative languages?

    • ahartmetz 9 minutes ago

      If you can mostly stick to the declarative way, it's still a benefit. No Turing-complete language completely prevents you from writing "bad" code. "You are not completely prevented from doing things that are hard to understand" is a bad argument. "You are encouraged to do things that are hard to understand" is a good one (looking at you Perl).

    • noelwelsh an hour ago

      OP is not being very precise (and in a way that I don't think is helpful). There is nothing imperative in an if expression. Declarative languages can be Turing complete. Declarative languages are a subset of programming languages.

    • lionkor 3 hours ago

      Wishful thinking? Maybe they are tired of all this and want to make something good again, and so the cycle continues.

    • xienze 18 minutes ago

      It’s the cycle of newcomers to <field> looking at the existing solutions and declaring “this shit is too complicated, why did these morons design it this way? Check out my DSL that does everything and is super simple!”

      Then time passes, edge cases start cropping up and hacks are bolted on to accommodate them. Eventually everything struggles under the weight of not having loops, conditionals, etc. and those are added.

      After some time, the cycle begins anew.

chipx86 3 hours ago

I'm pretty happy to see this, as conditionals can really help keep code manageable when trying to define CSS variables or other properties based on combinations of light mode, dark mode, high-contrast, contextual state in a document or component, etc.

if() isn't the only way to do this, though. We've been using a technique in Review Board that's roughly equivalent to if(), but compatible with any browser supporting CSS variables. It involves:

1. Defining your conditions based on selectors/media queries (say, a dark mode media selector, light mode, some data attribute on a component, etc.).

2. Defining a set of related CSS variables within those to mark which are TRUE (using an empty value) and which are FALSE (`initial`).

3. Using those CSS variables with fallback syntax to choose a value based on which is TRUE (using `var(--my-state, fallback)` syntax).

I wrote about it all here, with a handful of working examples: https://chipx86.blog/2025/08/08/what-if-using-conditional-cs...

Also includes a comparison between if() and this approach, so you can more easily get a sense of how they both work.

culi 11 hours ago

Far from being ready when only one major browser supports it. If you want this, you should vote for it to be focused on for interop-2026

https://github.com/web-platform-tests/interop/issues

Right now, the leading CSS proposals are `@container style()`, `corner-shape` and `break-after`

https://foolip.github.io/interop-reactions/

  • StoneAndSky 7 hours ago

    The People have spoken, and they want squircles.

  • hdjrudni 9 hours ago

    Yeesh.. I've definitely tried using break-after and being disappointed it didn't work properly. The amount of hoops I had to jump through to get things to print properly on paper...

    • fuzzfactor 26 minutes ago

      >The amount of hoops I had to jump through to get things to print properly on paper...

      Anybody know how that compares to Report Definition Language?

      https://learn.microsoft.com/en-us/sql/reporting-services/rep...

      Seems like an awfully scattered shitshow just to arrive at a typical "What You See Is Not What You Get" result.

      And this one is made for printouts.

themafia 11 hours ago

It's a great way to make conditional styles without having to use JavaScript; however, having used JS for years to make theme color and icon sets that rely on CSS properties, I'm not sure I particularly like this method. I feel like you have to smear a lot of logic across your CSS whereas with JS you can reduce your theme to a data structure and just have a simple function to setup all the CSS variables based on that.

Am I just an old man?

  • pie_flavor 42 minutes ago

    You're pulling the old man card on CSS-in-JS? Putting your style logic in CSS is what CSS is for, CSS-in-JS is an annoying hack to make React work. What this is replacing is SCSS.

    • masswerk 32 minutes ago

      Well, historically, styles were first in JS (JS StyleSheets in Netscape 4.0) and were pulled out into CSS. – This is an old man card! ;-)

  • bawolff 8 hours ago

    The primary goal is to just have a more concise way to do @media queries. Its not intended as a replacement for most uses of JS

    • 6031769 3 hours ago

      If we've learned anything from the history of CSS, JS and the semantic web it is that 99% of the time a feature will be used in ways that were not intended. There is no reason to suppose that this will be any different.

  • functionmouse 10 hours ago

    I like making static informational pages and don't know the first thing about JavaScript, so this could be handy for me.

  • mmis1000 9 hours ago

    Javascript always suffer from FOUC problem though (Unless it's server side). Although the if() css function seems to just be syntax suger of standard @media query. So it doesn't really add anything to solve existing problems.

    Edited: It seems it can also be toggled from css variable? So it might actually fix some existing problems.

    • mikestorrent 6 hours ago

      How hard would it be to have a response header that tells the browser "don't display anything at all until we ask you to from JS when we're ready"?

      Considering the kinds of crap that have been done with headers...

      • Tajnymag 5 hours ago

        Would it be enough to have <body> hidden using an inline style in the initial html response and when everything is loaded, one would remove the style using javascript?

      • coke12 5 hours ago

        Many sites do something like that in practice. The problem is the extra 500ms of parse+eval time for your JS bundle influences user behavior a lot on the margin, so it’s better to not force the user to wait.

      • account42 4 hours ago

        How hard would it be to use JS for progressive enhancement instead making your website depend on it to display simple text and images.

      • mmis1000 5 hours ago

        Practically only cordova does these for now. But it's a native app so of course it can do whatever it want.

  • kevin_thibedeau 10 hours ago

    Just use SCSS to smear the logic across CSS automatically.

bingemaker 8 hours ago

I'm not sure turning CSS into a full blown language is a good idea. With all the cascading in place, it is already a bit hard to determine why certain styles are applied. Now with this, we will be spending more brain cells debugging CSS issues.

  • lmm 8 hours ago

    On the contrary, a lot of the reason CSS is confusing is because it's full of insane hacks people have to do to get the behaviour they want. A straight-up if statement is much simpler than many of the horrors I've seen.

  • adgjlsfhk1 7 hours ago

    css definitely shouldn't have backwards branches (loops/recursive functions), but adding a little more power can clean up expression a ton and make reading/applying that much faster

    • lenkite 6 hours ago

      I wish the "little more power" would add CSS modules. It would also be great if web components didn't require Javascript and could be configured with pure HTML and CSS.

      I will kiss the feet of the whatwg groups if they do this.

      PS: Would also love to have declarative template inclusion now that removal of XSLT has also removed this facility from the browser.

EmilStenstrom 5 hours ago

Here is a much better link to how it works: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...

  • cubefox 3 hours ago

      padding: 1em;
      padding: if(style(--size: "2xl"): 1em; else: 0.25em);
    
    > Note: Remember to include the else condition. In if()-supporting browsers, if no else value were included and --size was not equal to "2xl", the padding would be set to initial.

    This is counterintuitive. You would expect the above falls back to "1em" (from "padding: 1em;") when "else" is not specified. Instead, omitting "else" apparently means "else: initial".

Incipient 5 hours ago

As long as css remains "so fast it's free" then I'm mostly happy with that - I use css without thinking about optimisations, and I like it like that!

  • Sesse__ 4 hours ago

    You can certainly write slow CSS, and people do :-) JavaScript typically takes up more of the CPU time overall, though.

  • cryptonym 4 hours ago

    It's not free at all. You can profile it with debug tools and find the most expensive selectors to refactor them. You can also write CSS animations that impacts performance/user experience, this can also be profiled.

    Sorry but if you use advanced feature and especially on a big DOM, you have to think about optimisations.

stevefan1999 11 hours ago

With the inclusion of branches, is it possible to say that CSS is now even more Turing-Complete? Now we just need to find ways to do recursion/targeted jumps so that it is finally recursive-enumerable

xnx 10 hours ago

If we could do it over, knowing that we'd eventually get to this point, would https://en.wikipedia.org/wiki/JavaScript_Style_Sheets have been the better path?

  • bawolff 8 hours ago

    I would say no. I think CSS is a good language and made good choices.

    And honestly we already essentially have this with CSS related apis in js. The examples in that article are basically identical to how you set css in js on modern web browsers with slightly different naming conventions.

  • inopinatus 9 hours ago

    If I had a time machine I would go back and ensure that DSSSL (https://en.wikipedia.org/wiki/Document_Style_Semantics_and_S...) was the standard that got up.

    • watersb 9 hours ago

      All hail the embedded Scheme interpreter to apply Style transformations!

      Although I feel like we've already explored this with XSL. The XML syntax was perhaps too much to swallow.

    • runarberg 9 hours ago

      You write your markup in an xml syntax, your scripts in a C syntax, and your styles in a lisp syntax... a perfect trio.

  • shiomiru 4 hours ago

    I actually wonder if transpiling calc/min/max/etc. expressions to JS is a viable path to implementation, considering that you already need a fast interpreter for these.

nottorp 5 hours ago

So we were looking in the wrong direction for AGI!

tanin 3 hours ago

Nice. I've built desktop apps in a few other frameworks e.g. Java Swing, JavaFX, JetBrains Compose, SwiftUI, QT. Nothing is as easy as JS/HTML/CSS. I've realized that the main reason is its robust capabilities e.g rich auto-layouting/positioning capabilities.

Meanwhile in other UI frameworks, you either don't do it or you draw the damn things yourself lol. So, most of the times I'd just not do it.

Adding if is great. It would reduce the need for JS a bit more, which would make the code more maintainable.

Aardwolf 3 hours ago

Can it already vertically and horizontally center unknown-beforehand-length multi-line text in a single html element, just like non-CSS table cells could already in 1995?

  • JimDabell an hour ago

    > Can it already vertically and horizontally center unknown-beforehand-length multi-line text in a single html element, just like non-CSS table cells could already in 1995?

    Non-CSS table cells have never been able to do that – you need a wrapping <table> at minimum for browsers to render it how you want, a <tr> for it to be valid HTML, and <tbody> comes along for the ride as well as an implied element. So that’s four elements if you want to centre vertically with <td> or <th>. If you wait until the year 2000, then you can get that down to three elements by switching from HTML to XHTML because <tbody> is no longer implied in XHTML.

    CSS, on the other hand, has been able to do what you want since 1998 (CSS 2) with only two elements:

        <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
        <title>.</title>
        <style type="text/css">
    
            html,
            body {
                height: 100%;
            }
    
            .outer {
                display: table;
                width: 100%;
                height: 100%;
            }
    
            .inner {
                display: table-cell;
                vertical-align: middle;
                text-align: center;
            }
    
        </style>
        <div class="outer">
            <div class="inner">
                Test<br>
                Test<br>
                Test<br>
                Test<br>
                Test<br>
                Test
            </div>
        </div>
    
    (I’m using a <style> element here for clarity, but you can do the same thing with style attributes.)

    https://www.w3.org/TR/1998/REC-CSS2-19980512/

  • mubou2 2 hours ago

    align-content: center;

    (supported on block elements since sometime last year)

marcinignac 2 hours ago

Proposed title change "Chrome now has an if() conditional function in CSS"

James_K 32 minutes ago

How about giving me the option to use variables in media queries?

  • sethops1 6 minutes ago

    Yeah this one seems like such low hanging fruit and would be a great convenience.

zuhsetaqi 5 hours ago

It's a working draft and only available in Chromium ...

manucardoen 3 hours ago

Somewhere, someone has just started porting Doom to CSS.

neuralkoi an hour ago

Quick, someone get DOOM running on CSS!

jsmailes 4 hours ago

If I'm reading this correctly, Opera added support in an earlier version then took it away again. Any idea why they might have done it? Maybe a browser engine change under the hood?

mr_windfrog 9 hours ago

I'm not really sure I understand this. How is the new if() conditional function different from using @media (width ...) when adapting layouts to browser width?

  • bawolff 8 hours ago

    Its basically the same, just more convinent syntax.

    I think if can also do string equality on variable values, which is a bit new but also niche. The main point is just to do @media but inside a property decleration.

layer8 2 hours ago

I guess we can now write Excel in CSS.

  • fuzzfactor an hour ago

    Interesting, a few organizations can (very) carefully craft their own LOB software over the number of years it can take to fully free themselves from Excel. And then realize the intended advantage for years to come.

    At the same time over a period of years the web approach is to make the whole thing more like a bunch of interlocked Excels, more so than it already was before.

    Does that mean any resulting disadvantage during following years is intentional? Any more than huge orgs grew to depend on Excel, one physical desktop at a time since that was the only thing in common among all those diverse desk owners that would do the job, plus it was the first thing to come along to fill that niche.

qwertytyyuu 2 hours ago

oh no, this is going to cause abomninations,

silverwind 7 hours ago

This is missing a "if variable equals" imho. Right now it seems like pure syntactic sugar for a media query.

  • ramesh31 7 hours ago

    >This is missing a "if variable equals" imho.

    This is exactly what it does not need. SASS style conditional CSS is a complete nightmare to maintain. The declarative nature is one of its greatest strengths.

zb3 11 hours ago

Not supported in Firefox and Safari. Also it seems most people forget that the more bloated the web platform is, the more resources are needed to develop and maintain a web browser engine.. Chromium is open-source, but it's already expensive to maintain a fork or even rebuild it..

  • lenkite 6 hours ago

    They just need to start deprecating and removing old features. They had no issues with XSLT removal even when some major sites like the library of congress used it. So the excuse of backward compatability has already proven to be a lie.

    • tgv an hour ago

      Yeah. Font-size and width, be gone!

  • zeroCalories 11 hours ago

    [flagged]

    • zb3 10 hours ago

      > How did this happen?

      That's pretty simple - Google has poured tons of money into Chrome and Mozilla. Google is not a charity so this was a strategic investment.

      > You should go over to the CSS working group and let them know

      That wouldn't work, money is what ultimately matters there.

      • zeroCalories 9 hours ago

        [flagged]

        • singpolyma3 9 hours ago

          lol. What other browser vendors? Whatwg is just google is a trench coat. Edge is chrome. Firefox is funded by Google. So I guess apple who's main contribution is being years behind and having half their stuff be broken

          • zeroCalories 9 hours ago

            There's this really cool site where you can see how well supported a feature is: https://caniuse.com/?search=if

            If Google controls everything, why is if() only supported on 59% traffic? Do you think any serious company will let their site break on 40% of clients? Do you think Apple's opinion is unimportant?

            • homebrewer 6 hours ago

              Did you look at detailed usage stats? More specifically at things that do not count towards that 59%: older versions of Chrome add another 20%, various Chromium forks add a few percent more, so the rest of the internet accounts for less than 20%. I'd say this is pretty monopolistic for one company to control the means of more than 80% of traffic of doing its 'trafficking'.

        • zb3 9 hours ago

          > And the other browser vendors with conflicitng interests just go along with it?

          When there's a conflict of interest they don't (Apple refuses to implement some APIs that would help making their walled garden app store more obsolete). But just maintaining a duopoly (Mozilla is funded by Google) is not a conflicting interest itself.

          > Did you come to that opinion after engaging in the discussions with them?

          With employees? There's no point. If you have a well paid job you will never accept the fact that what you're doing might not be so good after all..

          • zeroCalories 9 hours ago

            > When there's a conflict of interest they don't (Apple refuses to implement some APIs that would help making their walled garden app store more obsolete). But just maintaining a duopoly (Mozilla is funded by Google) is not a conflicting interest itself.

            What makes you think Apple wants to maintain any sort of duopoly? Do you think they're happy that Edge became a Chrome skin?

            > With employees? There's no point. If you have a well paid job you will never accept the fact that what you're doing might not be so good after all..

            Damn, so you haven't even tried discussing your issues with the people responsible? You seem to have a really strong opinion on something you haven't engaged with at all.

foreigner 6 hours ago

Can these be used inside inline style attributes?

aanthonymax 6 days ago

This support has appeared in the new W3C specification.

darig 8 hours ago

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