classes as assertions

[Anniepoo]

This is a half formed thought as I'm headed to bed, putting it out for people to poke at.

One very common manipulation for js is to add and remove classes - and many status changes are best indicated that way.
Say I have an input field that's given a class when it's input isn't valid, something that has to be tested on the server.

The server pengine exposes invalid/1

option 1:

{|vue|| <input class="someclass @invalid(this.value)" ... />  |}

option 2:

{|vue|| input(class([someclass, @invalid('this.value')]), name(username), ...], [])  |}

Or, even sneakier -
a declarative

:- vuelog_class  invalid("this.value").

which means 'if you see invalid in the source html classes, make a pengine call and if it succeeds,
add the class invalid. The arguments to the call are the javascript expressions in the strings

lots of questions - is the class initially present? How does it decide to render?

But the core of the idea is that classes are predicates for html. Why not treat them as prolog predicates?

[Anniepoo]

OK, more cogitating.

We can logically describe a part of the DOM as being conditional using implication and deontic logic.

% the myattribute attribute of everything with myclass must be myvalue when some_prolog_on_server
% is true.

.myclass["myattribute"] = X  :- 
    some_prolog_on_server.

// set the contents of mywarning 
#mywarning.innerhtml = "<p>dont do that!</p>" :- other_prolog_pred.

// set the contents of UL.mytodos to a list of the proofs of nondet_pred.
// if X is a solution to nondet_pred, tthen there exists an element of the dom whose
// innerhtml is X within UL.mytodos LI.atodo
UL.mytodos  LI.atodo = { innerhtml: X, margin: 0; } :- nondet_pred(X).

I wonder if this can be done with a quasiquote and the usual surrounding with deontic.

[Anniepoo]

ok, may have worked out a way to make this computationally tractable over dinner tonight, but need to sleep on it. The napkin's in my purse.
Gist of it is codewalking and bumping the generation # of stateful things.