you cannot create a composable simply from javascript in Compose For Web, right? eg

download("some_page/compose-app.js")
run("app.js")

What do you mean? Your compose web app is just a regular kotlin js project resulting in a normal js file you can fetch and run.

could such be used for a scriptable ui binding such as lua

If you are able to connect lua with js, sure.

would such benifit from recomposability ?

Could you please say, what you really try to archive? All the questions are somehow vague. I don't know how you want to execute lua in your browser and how to pass parameters from Lua to Kotlin. Compose is a Kotlin specifc compiler plugin for Kotlin code. You can use Compose Web to use declartive @Composable functions rendering UI in your browser written in Kotlin. Of course you can dynamically change the UI based on data.

alright

It depends. First at all, Compose is a Kotlin compiler plugin to create a tree changing over time. If you want to use this tree to get UI, you use this tree to render your underlying UI, for example on web it is plain hmlt dom, and on android and desktop skia (a c grafic lib) is used. Of course, the wrapper needs to be written in Kotlin.

for example, creating the UI from JNI interop calls,

JNI <-> Java/Kotlin -> UI api

It really depends what you are passing over JNI. Of course you can pass data and create your views like you do with any other data source. If you want to call the composable functions directly from jni, don't do it.

eg

void * text = CreateText("hello"); // creates text object on java/kotlin side
void * box = CreateBox(); // creates box object on java/kotlin side
AddComponent(box, text); // reparents [text] to [box] such that [box] contains 1 child: [text], on java/kotlin side

Compose is declarative based on data. Your code is imperative based on function calls. So no, calling compose functions from JNI does not work at all. You should pass the data you want to show over JNI.

alright