is it possible to create a .kts/kt config file and...

# gradle

[Alex Styl]

is it possible to create a .kts/kt config file and use that during some sort of gradle task? my project is a compose multiplatform project

i would like to do what settings.gradle.kts does (how it gives the users the way to configure their build), but I cannot find any documentation on this or how to start.

[mbonnin]

Are you looking at scripting? https://kotlinlang.org/docs/custom-script-deps-tutorial.html#create-a-scripting-host

[hfhbd]

I decided to not use scripting but instead I use a normal main class/function with a custom JavaExec task because it’s way easier to setup than a custom scripting host. Downside are implicit properties/receivers, if you really need them. Otherwise, just generate custom code and add them to the srcDir.

[hfhbd]

I also guess, you can’t cache the scripting compiled classes, but you can cache the JavaExec/Kotlin classes because it’s a normal gradle task.

[Alex Styl]

@mbonnin im lost. what would the script be in this case and how could i import that in the gradle task?

I am working on a library and I want to give my users a way to configure the library during build time (generate code).

I was thinking of having some sort of kotlin class outside of the source set where people can set the configurations they need (if any)

[Alex Styl]

writing the config in kotlin for the users would be ideal. still trying to figure out how this would work (if it can work)

[Vampire]

What should this script configure?
The build?

[mbonnin]

Does the user configuration need to be turing complete? Or is it just data?

[Alex Styl]

What should this script configure?

Ideally this config will be in kotlin. i mentioned in the OP a kts file because that seems what settings.gradle.kts is using (i havent used kts on my own).

[Alex Styl]

@mbonnin what do u mean by turing complete?

[mbonnin]

Execute random algorithm

[Alex Styl]

actually, let me tell u specifics

[mbonnin]

Kotlin is good for algorithm, you have statements, loops etc

[mbonnin]

But if you need data input, other formats like json, toml, etc... are usually better suited

[Vampire]

Ideally this config will be in kotlin. i mentioned in the OP a kts file because that seems what settings.gradle.kts is using (i havent used kts on my own).

I did not ask how the config should look like.
I asked what it should configure.

[Vampire]

What will be the effect of executing that script?

[Alex Styl]

But if you need data input, other formats like json, toml, etc... are usually better suited

@mbonnin gotcha. the only reason why i think kotlin is better is because of strong types, but reading what you said, im reconsidering

[mbonnin]

There’s been quite some discussions lately about declarative vs imperative configuration and declarative Gradle, amper, etc...

[mbonnin]

The tldr; is everyone loves Kotlin but it’s longer to compile and harder to write tooling around it. Declarative data languages have some value

[mbonnin]

I’d love to have a data language that reuses “most” of the Kotlin syntax though

[Alex Styl]

@Vampire I am working on this library which lets people configure their app's theming.

right now they can set up their design tokens (theming attributes) via kotlin like this:

val Theme = buildComposeTheme { 
colors = DesignTokens(
        primary to Color.Red
    )
}

i would like to be able to generate extensions functions for the users based on their desired theme. ie ComposeTheme.colors.primary

[Alex Styl]

currently this is done in runtime. trying to figure out ways of achieving the code gen. i think i would need a config on the build step of the project

[mbonnin]

Maybe codegen with KSP?

[Alex Styl]

can KSP run annotated code? it only parses right?

[mbonnin]

You can generate code in a KSP processor so it can look at the existing constructs and augment them

[mbonnin]

This is how Moshi generates JSON parsers for an example

[Alex Styl]

brilliant. forgot completely about Moshi. need to check

[mbonnin]

If you have a pattern in the user code that you can identify, you can generate code using kotlinpoet and turn runtime behaviour into compile-time behaviour (and fail the build if some constraints are not satisfied)

[mbonnin]

Not 100% sure it’ll work for your use case though, it depends what you want to codegen

[mbonnin]

Especially, I’m not sure KSP can look “inside” function bodies, it’s mostly about signatures

[hfhbd]

No, KSP doesn’t look inside the function body

[Alex Styl]

thanks for the help folks. got a few nice ideas on how to move forward

[ephemient]

there's no shortage of non-turing-complete declarative languages and some of those are typed. https://cel.dev/ for example, although there isn't a Kotlin implementation (you'll have to use a Java implementation or build your own)

[Vampire]

Or the shiny new Pkl 🙂