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.
> every declarative language becomes a programming language.
Overly pessimistic, lots of non-programming languages remain non-programming languages. Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down...
> The distinction between code, config and data is being erased.
As as lisp programmer, I love it. Get rid of treating things differently, make everything the same and make everything work with everything, code should just be data.
The web should always have been a programming language, with all the usual constructs available in both the display and markup layers.
But instead of a single unified standard library for the industry we got a sprawling, ludicrous mess of multiple poorly thought-out semi-compatible technologies, with an associated sub-industry of half-baked fixes and add-ons.
> with all the usual constructs available in both the display and markup layers.
I'm glad the transition to mobile web accelerated on more battery efficient GPUs was possible due to the model instead of Alan Kay's idea that websites should render themselves, where each website would have needed to be upgraded for GPU support for compositing.
Because modern UI toolkits like Flutter proved that UI should just be code, not separated into three different languages. In this case, adding conditionals can remove the need for js in some cases, which is good.
So instead of having a css for x which defines e.g. dark mode and light mode separately, you can now define it via a single css rule.
Where previously the "tree" forked at the beginning and attributes were set multiple times, depending on various criteria - now you set it once, and evaluate it's value depending on criteria
If only Lisp had better presense in modern code editors. Emacs is not enough, especially on Windows where it is super slow. I think this is what actually stops newcomers to start with Lisp and not Python
> I think this is what actually stops newcomers to start with Lisp and not Python
What stops newcomers is knee-jerk reactions about the (lack of) syntax, it's scary to see something that doesn't look like Algol, because everyone who does mainstream programming uses Algol-like languages.
Introduce lisp to anyone who knows programming since earlier, and 99% of them will have a adverse reaction to s-expressions, before they understand what's going on. Once they understand, it makes a lot of sense obviously, but not everyone even has that kind of open mindset where they could understand if they wanted to.
I spent more time than I'm willing to on large Terraform projects. How exactly is this relevant to declarative vs imperative or even my comment at all? I don't see what the "gotcha" is supposed to be here.
You make bad comments because I can't understand the point you're trying to make. I'm am engineer, I make choices based on informed tradeoffs, anything else would be sub-standard. Not sure why you think I only consider advantages, but I'm afraid asking you for clarification will just lead to more ramblings.
It is a configuration language with general programming features, but it is decidedly _not_ Turing complete. It seems to sit at a sweet spot between "just JSON, no programming convenience at all" and "full-blown programming language with nontrivial toolchain".
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.
Ant did not include IF THEN ELSE, unless you added the contrib package.
If you understood the paradigm, you could write branches in Ant files simply using properties and guards on properties ("unless"). Using IF in Ant was basically admission of not having understood Ant.
This said, I used Ant for a very limited amount of time.
For new .NET SDK style projects you hardly ever need to customize the defaults and I know it's used for more stuff than .NET, but I just wanted to give an example where it actually doesn't suck. Also, you may not need to do everything in MSBuild, for some more complex stuff, you can use something like Cake (https://cakebuild.net/) in .NET for example and skip the programming in XML.
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.
"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.
> All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.
"Huh?" I asked myself when you mentioned that Terraform is now imperative somehow. Took a look at the website again, and seems to still be HCL, and still be declarative. Am I missing something? How exactly is Terraform today a "imperative monstrosity"?
> Terraform has modules which are an elaborate method of doing function calls
... What? How is modules a function call? It's just a hierarchy, everything about/with modules is still declarative.
> HCL 2 has loops and conditionals. It is most definitely imperative.
So what? Just because there is loops and conditionals doesn't mean it's suddenly imperative.
How exactly you do loops in HCL? Last time I used it, you still used declarative configuration for that, and use `for_each` as an declared option, you don't "call for_each which returns config", all that happens inside of HCL/TF, because it is declarative.
Did something change like yesterday or are people even here on HN so ignorant about what declarative vs imperative actually means?
You "call" a module with arguments. You can call them multiple times. In every way that matters they are just like a function call.
I don't understand why there is a distinction between for each in a standard language vs for_each in HCL2. They are both do something by iterating over something else at runtime. The syntax isn't what matters here.
I think maybe you are mistaken in your own distinction between declarative and imperative.
Imperative: Tell the computer how to do something, by instructing it what to do.
Declarative: Tell the computer what you want the result to be like, and the computer figures out how to do it.
for_each in Terraform is very much declarative, just like modules. Compare how you'd do the same thing with JS or any other (imperative) language you know, and I think it must be clear what the difference between the two is.
Those boundaries are pretty fuzzy. The complexity of the logic with conditionals and loops in a module means that you have pretty much stopped describing what it should like and instead described how to make it look the way you want it.
I have read terraform modules where I had to execute the logic to know what got produced which moves it from your imperative description to the declarative description as far as I'm concerned.
You need unbounded recursion. Conditionals alone can’t do that. If you have some kind of conditional go to/jump if expression that’s a different matter.
FWIW, you can make software that runs on Harvard architecture chips. They feature distinct address spaces for ROM and RAM. It's been a while, but it's how Atmel/Microchip AVR micros work.
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.
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.
It was shocking the first time I showed a lisp program to a (particularly "annoyed by everything") non-lisp developer who never apparently saw s-expressions before. Lots of knee-jerk reactions of "Oh my god so many parenthesis" and "How could anyone program like this?" while they sat there smug with their TypeScript codebase having more special characters, syntax and the same amount of parenthesizes, only because the opening parenthesis is one symbol to the left, instead of in the middle of the calls...
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).
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.
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.
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).
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...
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.
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.
You have to consider why, and the answer was often "there's no other way".
The paths of least resistance on the web are now very different. These features were not delayed due to implementation details, but a deliberate shepherding of the standards. The most powerful features were saved for later and even still this is scoped to media queries, etc. only.
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.
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?
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.
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.
> 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".
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.
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.
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
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.
Well, you can actually write slow css if you make real deep nested flex container. And it's not even too rare. You can actually find such example in yhe wild.
The spec of flex layout requires it to layout its child elements several times to compute actual layout. Make it deep and nested without proper constrains will results in n*n*n*n… layout computations and bring down the browser on resize.
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.
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
Don’t apply programming language mental models onto CSS features.
CSS if() probably just merges one of two single-property RuleSets onto the parent RuleSet depending on the condition, which has nothing to do with branching, as there is no execution flow to branch.
Huh. 35 year ago I was the sole maintainer of an in-house SQL-like database query language. The application was transforming relational data into a more concise and efficient format for use in an embedded application (AT&T 5ESS digital switch). All the mapping was done in this SQL-like language. One of my power users mentioned the difficulty they had in actually changing logic based on the values in the database. For example, to perform different logic based on whether a column was a 1 or a 2, they'd have to write two querys: one for 1 and another for 2. Possible, sure, but not very clean or efficient. To address this, I implemented an if() function.
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.
Knowing what we know, we would probably have stepped out of our time machine to make sure that Brendan Eich kept the Scheme-based syntax and added semantic HTML enrichment for styling, sparing untold grief over the last generation...
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.
Probably not. There is a lot of optimizations browsers do to make the stylesheets super fast[1], and I think quite a few of those rely on CSS not being Turing complete.
Replying to myself (hey, I like myself and I'd like to have a conversation with me):
CSS doesn't have it right? Just Chrome.
Considering how all kinds of "experts" have started to make web sites that only work fine in Chrome [1], this is not exactly a useful new feature, more like embrace and extend...
[1] Orange Romania, when will I be able to download my invoices again in Firefox?
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?
> 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.)
Thanks, seems to work at first sight in combination with text-align for the horizontal alignment!
That means I may finally not need line-height or multi-element tricks for this anymore
Interesting that this is finally there since a year!
I wonder what made them decide to support it finally, since CSS's creation in 1996.
A button never looks professional if the text in it isn't centered, this was a really needed feature and I still can't understand why it took that long
Edit: it does seem worrying that for me this property vertically centers but not horizontally while the description of it doesn't say vertical but is: "The items are packed flush to each other in the center of the alignment container along the cross axis."
I mean elements with a width set in pixels, ems or some other unit. Setting width to 'fit-content' would override the width you set and then the element may overlap others to the right of it
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?
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.
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?
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.
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..
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.
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
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?
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'.
> 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..
> 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.
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.
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.
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.
> every declarative language becomes a programming language.
Overly pessimistic, lots of non-programming languages remain non-programming languages. Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down...
> The distinction between code, config and data is being erased.
As as lisp programmer, I love it. Get rid of treating things differently, make everything the same and make everything work with everything, code should just be data.
> Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down.
The question still is: why is CSS becoming a programming language? And who decides on this, anyway?
Becoming? CSS is already Turing-complete (https://stackoverflow.com/a/5239256), even without if() function.
Why? Because of enormous JS bloat. Pure CSS solutions are more performant and backwards-compatible (don't raise exceptions which abort the code).
Who decides? CSS Working Group.
The web should always have been a programming language, with all the usual constructs available in both the display and markup layers.
But instead of a single unified standard library for the industry we got a sprawling, ludicrous mess of multiple poorly thought-out semi-compatible technologies, with an associated sub-industry of half-baked fixes and add-ons.
> with all the usual constructs available in both the display and markup layers.
I'm glad the transition to mobile web accelerated on more battery efficient GPUs was possible due to the model instead of Alan Kay's idea that websites should render themselves, where each website would have needed to be upgraded for GPU support for compositing.
Because modern UI toolkits like Flutter proved that UI should just be code, not separated into three different languages. In this case, adding conditionals can remove the need for js in some cases, which is good.
Please provide evidence for that proof.
Considering how this is seems to be designed... I don't think that's the reason?
I mean looking at the mdn docs it's just a replacement for regular other syntax https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...
So instead of having a css for x which defines e.g. dark mode and light mode separately, you can now define it via a single css rule.
Where previously the "tree" forked at the beginning and attributes were set multiple times, depending on various criteria - now you set it once, and evaluate it's value depending on criteria
It looks like simple syntactic sugar to meI should have read the docs for it then. Thanks.
If only Lisp had better presense in modern code editors. Emacs is not enough, especially on Windows where it is super slow. I think this is what actually stops newcomers to start with Lisp and not Python
> I think this is what actually stops newcomers to start with Lisp and not Python
What stops newcomers is knee-jerk reactions about the (lack of) syntax, it's scary to see something that doesn't look like Algol, because everyone who does mainstream programming uses Algol-like languages.
Introduce lisp to anyone who knows programming since earlier, and 99% of them will have a adverse reaction to s-expressions, before they understand what's going on. Once they understand, it makes a lot of sense obviously, but not everyone even has that kind of open mindset where they could understand if they wanted to.
I find lisp to be a very non ergonomic language and am happy that python is the default.
>> Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down.
You need to look at a large terraform project.
I spent more time than I'm willing to on large Terraform projects. How exactly is this relevant to declarative vs imperative or even my comment at all? I don't see what the "gotcha" is supposed to be here.
> > The distinction between code, config and data is being erased.
> As as lisp programmer, I love it.
You make bad engineering decisions because you consider the advantages, but not the disadvantages. <https://news.ycombinator.com/item?id=29231493>
You make bad comments because I can't understand the point you're trying to make. I'm am engineer, I make choices based on informed tradeoffs, anything else would be sub-standard. Not sure why you think I only consider advantages, but I'm afraid asking you for clarification will just lead to more ramblings.
The disadvantages are in the post I linked to.
Alright, I guess I'll reply to that with another comment you can go and read then: https://news.ycombinator.com/item?id=38373081
Fun way of having a conversation.
An interesting example is the Dhall language: https://dhall-lang.org/
It is a configuration language with general programming features, but it is decidedly _not_ Turing complete. It seems to sit at a sweet spot between "just JSON, no programming convenience at all" and "full-blown programming language with nontrivial toolchain".
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.
- Visual Studio project files are XML files that are interpreted line by line, and can contain variables, branches, and loops. Hell on earth.
They are badly copied Ant build files.
Ant came first, then when Microsoft redid the VS project format, they created MSBuild.
As incredible as it may sound, Ant is still easier to deal with than MSBuild.
Ant did not include IF THEN ELSE, unless you added the contrib package.
If you understood the paradigm, you could write branches in Ant files simply using properties and guards on properties ("unless"). Using IF in Ant was basically admission of not having understood Ant.
This said, I used Ant for a very limited amount of time.
It sure did, you use conditions, no need for contrib.
https://ant.apache.org/manual/Tasks/condition.html
The else part is easily done by repeating and negating the condition.
Two other advantages of Ant that MSBuild lacks in a sane way to this day, are macros, and proper documentation.
The legacy version of MSBuild was really bad, but the modern MSBuild project files for .NET are actually quite concise and clean by default?
Only if you are happy with defaults and don't require any build logic.
Also you forgot MSBuild is used for everything, not only .NET.
For new .NET SDK style projects you hardly ever need to customize the defaults and I know it's used for more stuff than .NET, but I just wanted to give an example where it actually doesn't suck. Also, you may not need to do everything in MSBuild, for some more complex stuff, you can use something like Cake (https://cakebuild.net/) in .NET for example and skip the programming in XML.
Horrible. Would’ve been much nicer if they’d reached for Scheme.
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.
They don’t know how good they really have it :)
Wesnoth the game also has that via WML. Looks very ugly and obfuscated.
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.
CMake was never declarative AFAIK?
CMake today is effectively an eso-lang / Turing tarpit with some “modern” declarative conventions that people try to push.
"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.
I think cmake kind of needs conditional checks though.
> All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.
"Huh?" I asked myself when you mentioned that Terraform is now imperative somehow. Took a look at the website again, and seems to still be HCL, and still be declarative. Am I missing something? How exactly is Terraform today a "imperative monstrosity"?
Terraform has modules which are an elaborate method of doing function calls. HCL 2 has loops and conditionals. It is most definitely imperative.
This is not necessarily a problem except that they had to live in the original HCL v1 landscape which makes them awkward syntactically.
> Terraform has modules which are an elaborate method of doing function calls
... What? How is modules a function call? It's just a hierarchy, everything about/with modules is still declarative.
> HCL 2 has loops and conditionals. It is most definitely imperative.
So what? Just because there is loops and conditionals doesn't mean it's suddenly imperative.
How exactly you do loops in HCL? Last time I used it, you still used declarative configuration for that, and use `for_each` as an declared option, you don't "call for_each which returns config", all that happens inside of HCL/TF, because it is declarative.
Did something change like yesterday or are people even here on HN so ignorant about what declarative vs imperative actually means?
You "call" a module with arguments. You can call them multiple times. In every way that matters they are just like a function call.
I don't understand why there is a distinction between for each in a standard language vs for_each in HCL2. They are both do something by iterating over something else at runtime. The syntax isn't what matters here.
I think maybe you are mistaken in your own distinction between declarative and imperative.
Imperative: Tell the computer how to do something, by instructing it what to do.
Declarative: Tell the computer what you want the result to be like, and the computer figures out how to do it.
for_each in Terraform is very much declarative, just like modules. Compare how you'd do the same thing with JS or any other (imperative) language you know, and I think it must be clear what the difference between the two is.
Those boundaries are pretty fuzzy. The complexity of the logic with conditionals and loops in a module means that you have pretty much stopped describing what it should like and instead described how to make it look the way you want it.
I have read terraform modules where I had to execute the logic to know what got produced which moves it from your imperative description to the declarative description as far as I'm concerned.
CSS is already a programming language long before if() function. You can even emulate CPU in it: https://dev.to/janeori/expert-css-the-cpu-hack-4ddj
Conditional expressions are declarative. For example, every template language worth its salt has conditionals.
A programming (i.e Turing complete) language requires recursion or a construct of equal power.
There is no recursive program that can't also be created by adding in more conditionals. It's turtles the whole way down.
You need unbounded recursion. Conditionals alone can’t do that. If you have some kind of conditional go to/jump if expression that’s a different matter.
You have to give it to CSS, it's held out for a lot longer than most.
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
But then why was it added?
> The distinction between code, config and data is being erased.
This distinction never existed in LISP. Greenspun's tenth rule in action.
dont be such a doomer
We can blame von Neumann (et al) and his infernal architecture, where memory stores both instructions and data.
FWIW, you can make software that runs on Harvard architecture chips. They feature distinct address spaces for ROM and RAM. It's been a while, but it's how Atmel/Microchip AVR micros work.
https://en.wikipedia.org/wiki/Harvard_architecture
That said, I'm unaware of any programming language (outside assembler) that takes that split to heart in a higher-level way.
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.
You need more than if for Turing completeness though.
You need conditionals and loops. Recursion counts as looping.
Correct. You need at least 2 ifs.
You need unbounded recursion no?
That's actually what two ifs could be.
Was the case against the goto statement so good we can't mention it?
Or lambda. Or Forth commands. You can create an 'if' with few atoms.
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.
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.
Those who don't use lisp are destined to re-invent it - poorly.
Configuration complexity clock
https://mikehadlow.blogspot.com/2012/05/configuration-comple...
Unfortunely too many people are afraid of opening parentheses being posited on the far left instead of the middle of the text.
It was shocking the first time I showed a lisp program to a (particularly "annoyed by everything") non-lisp developer who never apparently saw s-expressions before. Lots of knee-jerk reactions of "Oh my god so many parenthesis" and "How could anyone program like this?" while they sat there smug with their TypeScript codebase having more special characters, syntax and the same amount of parenthesizes, only because the opening parenthesis is one symbol to the left, instead of in the middle of the calls...
I've been observing this, off and on, for decades now. Is there an actual formal proof or law named after someone at this point?
can someone interpret this as not a skill issue?
i want better, declarative, interactive, fast UIs
CSS is the best answer we have
So why do people still design declarative languages?
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).
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.
Wishful thinking? Maybe they are tired of all this and want to make something good again, and so the cycle continues.
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.
“Now”? This has always been the case.
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.
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/
The People have spoken, and they want squircles.
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...
>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.
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?
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
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.
You have to consider why, and the answer was often "there's no other way".
The paths of least resistance on the web are now very different. These features were not delayed due to implementation details, but a deliberate shepherding of the standards. The most powerful features were saved for later and even still this is scoped to media queries, etc. only.
I like making static informational pages and don't know the first thing about JavaScript, so this could be handy for me.
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.
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...
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?
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.
How hard would it be to use JS for progressive enhancement instead making your website depend on it to display simple text and images.
Practically only cordova does these for now. But it's a native app so of course it can do whatever it want.
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.
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! ;-)
Just use SCSS to smear the logic across CSS automatically.
God forbid we use html5
There is no HTML5 other than a buzzword: https://html.spec.whatwg.org/dev/introduction.html#is-this-h...?
Here is a much better link to how it works: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...
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".
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.
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.
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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
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.
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!
You can certainly write slow CSS, and people do :-) JavaScript typically takes up more of the CPU time overall, though.
Well, you can actually write slow css if you make real deep nested flex container. And it's not even too rare. You can actually find such example in yhe wild.
The spec of flex layout requires it to layout its child elements several times to compute actual layout. Make it deep and nested without proper constrains will results in n*n*n*n… layout computations and bring down the browser on resize.
It’s not even that hard. Use flex for layout and you can instantly see how slow reflow becomes when resizing the window.
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.
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
Don’t apply programming language mental models onto CSS features.
CSS if() probably just merges one of two single-property RuleSets onto the parent RuleSet depending on the condition, which has nothing to do with branching, as there is no execution flow to branch.
Doom on CSS when?
You can maybe run ZMachine games (not just Zork, there are several better games there) under zmachine.ps, written in PostScript.
And, maybe, in a TTF font.
Huh. 35 year ago I was the sole maintainer of an in-house SQL-like database query language. The application was transforming relational data into a more concise and efficient format for use in an embedded application (AT&T 5ESS digital switch). All the mapping was done in this SQL-like language. One of my power users mentioned the difficulty they had in actually changing logic based on the values in the database. For example, to perform different logic based on whether a column was a 1 or a 2, they'd have to write two querys: one for 1 and another for 2. Possible, sure, but not very clean or efficient. To address this, I implemented an if() function.
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One of the nice things working in vite is realising, “hey, this config file is just {Java,Type}Script”.
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?
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.
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.
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.
You write your markup in an xml syntax, your scripts in a C syntax, and your styles in a lisp syntax... a perfect trio.
Knowing what we know, we would probably have stepped out of our time machine to make sure that Brendan Eich kept the Scheme-based syntax and added semantic HTML enrichment for styling, sparing untold grief over the last generation...
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.
Probably not. There is a lot of optimizations browsers do to make the stylesheets super fast[1], and I think quite a few of those rely on CSS not being Turing complete.
1: https://hacks.mozilla.org/2017/08/inside-a-super-fast-css-en...
CSS is Turing complete :-) You can find pure-CSS implementations of Game of Life, for instance.
I don’t think that’s true, unless you count hardcoding the state evolution into CSS variables, one var per cell per step.
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So we were looking in the wrong direction for AGI!
Replying to myself (hey, I like myself and I'd like to have a conversation with me):
CSS doesn't have it right? Just Chrome.
Considering how all kinds of "experts" have started to make web sites that only work fine in Chrome [1], this is not exactly a useful new feature, more like embrace and extend...
[1] Orange Romania, when will I be able to download my invoices again in Firefox?
It's in the draft spec for the CSS Values and Units Module Level 5 (https://drafts.csswg.org/css-values-5/#if-notation)
I don't see Mozilla's or WebKit's positions anywhere, so this is a Chromium-only feature for now.
Curiously, Can I Use says:
> All major browser engines are working on implementing this spec.
However their official positions are absent:
https://github.com/mozilla/standards-positions/issues/1167
https://github.com/WebKit/standards-positions/issues/453
And Firefox’s bug for implementing it has no activity:
https://bugzilla.mozilla.org/show_bug.cgi?id=1981485
And Can I Use’s underlying data doesn’t have this note:
https://github.com/Fyrd/caniuse/blob/fedfb067aceccb2a5edadcc...
So it’s unclear why the Can I Use website is saying that everybody is working on it.
Maybe the site is "AI" generated now.
https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...
Proposed title change "Chrome now has an if() conditional function in CSS"
It's a working draft and only available in Chromium ...
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?
> 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:
(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/
align-content: center;
(supported on block elements since sometime last year)
Thanks, seems to work at first sight in combination with text-align for the horizontal alignment!
That means I may finally not need line-height or multi-element tricks for this anymore
Interesting that this is finally there since a year!
I wonder what made them decide to support it finally, since CSS's creation in 1996.
A button never looks professional if the text in it isn't centered, this was a really needed feature and I still can't understand why it took that long
Edit: it does seem worrying that for me this property vertically centers but not horizontally while the description of it doesn't say vertical but is: "The items are packed flush to each other in the center of the alignment container along the cross axis."
width: fit-content; margin: auto;
That changes the width, I guess I should have specified fixed width
What is a fixed with, that is not a has not a fix value?
I mean elements with a width set in pixels, ems or some other unit. Setting width to 'fit-content' would override the width you set and then the element may overlap others to the right of it
Then you just do width: <width in ems> em; ? I thought you didn't want to specify a width.
Not supported in Firefox
Is it Turing-complete yet? Seems close, but I've lost track.
https://gwern.net/turing-complete#:~:text=CSS
They want to turn it into a programming language ... :/
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?
If I'm reading it right, the if condition/predicate can check more things than @media() can.
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.
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?
Somewhere, someone has just started porting Doom to CSS.
I guess we can now write Excel in CSS.
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.
Nice, does it make turing complete? If so, another crap to block under Dillo.
That's what happens when you design a language by comitee (C++, JS) and try to do stuff in the web for a platform made to share static documents.
Just look at what kind of disasters the users faced with Office macros.
How long before CSS can run Doom?
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..
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.
Yeah. Font-size and width, be gone!
I think you mean "be gone" to only px based font-size right ? And instead of "width", use "inline-size". Instead of "height", use "block-size".
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> 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.
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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
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?
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'.
If you've ever ran a serious website you'd know most of those Chrome uses are poor third worlders that aren't worth much as users.
> 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..
> 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.
This is missing a "if variable equals" imho. Right now it seems like pure syntactic sugar for a media query.
>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.
Did you guys read the docs? It literally does have this albeit the syntax is a bit odd:
if(style(--foo: bar): baz)
Is how you test if variable --foo is equal to "bar"
See https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...
Quick, someone get DOOM running on CSS!
How about giving me the option to use variables in media queries?
Yeah this one seems like such low hanging fruit and would be a great convenience.
if (it's fast) { i'm excited }
Can these be used inside inline style attributes?
oh no, this is going to cause abomninations,
Next I want to run WASM inside CSS. W3C, please don’t disappoint.
Now we just need a while loop to make it turing complete.
Loops would be nice. To make cool fireworks animations with CSS, you basically need to use SCSS to CSS compiler: https://codepen.io/hmaw/pen/qBEMLxV
This support has appeared in the new W3C specification.
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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.