shevy-java on CSS as a Query Language

Hmmm. I kind of like CSS but I hate the creep-up of complexity.

It's not that I don't understand the rationale - any programming language offers more power than a non-programming language. But I'd rather think here that something else could instead replace all of HTML, CSS and JavaScript, rather than constantly wanting to make everything more complex. I don't use most of the new elements in HTML5, largely because I don't see the point in using specialized tags for micro-describing a webpage. I succumbed to the "it is a div-HTML tag and it has a unique ID"; that's what I think mots of those containers actually really are. I even wanted to have aliases to such IDs, simply to use as navigational href intralink.

    [data-theme="dark"] [data-theme="light"] :focus {
      outline-color: black;
    }

And I also don't like this. It takes my brain too long to process all of that. It is no longer elegant and simple.

On the other hand:

   h2 {
     color: red;
   }

That is still simple.

    So ancestor(X, Y) :- parent(X, Y). means: “For all possible values of X and Y, X 
    is an ancestor of Y, if X is a parent of Y.”

See - I already don't want to have to think in such terms. What is the :- anyway, looks like a smiley.

    @container style(--theme: dark) {
      .card { background: royalblue; color: white; }
    }

I stopped there.

I think this is a problem with CSS - too many people are ruining it. It is strange to see how standards that used to work, are degraded over time.

evncOP4mo

yeah I mean, to be clear, I'm less proposing "What if we add even more syntax and semantics to CSS" and more "what if we steal ideas from CSS, notice their similarity to logic / relational query languages, and use them to build something new". I probably could have articulated some of this better.

eg this example:

  [data-theme="dark"] [data-theme="light"] :focus {
      outline-color: black;
  }

means, in English/pseudocode, roughly: "If you have an element X with attribute data-theme="dark", and X has a child Y with attribute data-theme="light", and Y is focused, then the outline-color of Y is black".

so we could write this also as, e.g.:

  outline-color(Y, black) if 
    data-theme(X, "dark") and
    parent(X, Y) and
    data-theme(Y, "light") and
    focused(Y)

that's Datalog, except I went ahead and replaced :- with "if" and "," with "and".

if we want even more syntax sugar, we could do:

  Y.outline_color := black if
    X.data-theme == dark and
    Y.parent == X and
    Y.data-theme == dark and
    Y.focused

imagine `X.attr == val` <==> `attr(X, val)` as a kind of UFCS for Datalog to make it palatable to Regular Programmers, right

the declaration and scope of these variables is implicit here; if you want something even more ALGOL-family, we could write

  forall Y {
    Y.outline_color := black if 
       Y.data_theme == "dark" and
       Y.focused and
       Y.parent.data_theme == "light"
  }

here we've explicitly introduced Y, and made one of our joins implicit, and it looks even more like Regular Programming now, except the Datalog engine (or equivalent) is kind of running all these loops for you, every time one of their dependencies changes, in an efficient way ...

evncOP4mo

one more, for completeness:

  SELECT 'black' AS outline_color
  FROM elements parent
  JOIN elements child ON parent.id = child.parent_id
  WHERE parent.data_theme = 'light'
    AND child.data_theme = 'dark'
    AND child.focused = true

there's a lot of ways to express the same thing! it's interesting to notice the connections between them, I think, and their strengths and weaknesses, e.g. I probably wouldn't want to write my whole design system in SQL, but since it's relational queries over the elements structure and properties, you could.

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