Do you have plans to support unstructured code blo...

# ksp

[natario1]

Do you have plans to support unstructured code blocks? Like property initializers. For example given the class,

class Foo : Bar {
    val foo by bar()
}

It would be nice, from foo property, to retrieve the initializer "by bar()" as a code block / string that can be analyzed.

[Ting-Yuan Huang]

That's an interesting idea. Can you give some example of how those code blocks can be analyzed / from which what information can be extracted and used?

[natario1]

By analyzed I mean purely with string manipulation like regexes. Kind of what you can do in KotlinPoet with PropertySpec.initializer.toString().

If you want a concrete example, I have a library that lets you model Firestore database objects like this:

@FirestoreClass
class User {
    val firstName: String by this
    val lastName: String by this
}

A processor cycles over the properties to store their names, however sometimes the server field name is slightly different. It would be powerful to be able to write val firstName: String by this("first_name") and retrieve "first_name" in the processor, without adding verbose annotations to each field.

[Ting-Yuan Huang]

Generally, expressions are not available at the moment. The only available expression right now is within annotations, which are required to be compile time constants. In the example val firstName: String by this("first_name"), we would need to model function call and delegation before "first_name" can be retrieved. That (supporting expressions / statements) is beyond our current plan.

[natario1]

To be clear, I mean to expose an unstructured string, so that I could do:

val property: KSPropertyDeclaration = ...
val initializer: String = property.initializer 
// initializer is a string equal to "by this(\"first_name\")"
require(initializer.startsWith("by this")) { 
    "DB properties must be delegated to this!" 
}
val fieldName = initializer.substring(9, initializer.lastIndexOf("\""))

So you don't really need models for functions and delegation, it's just an opaque string, saying nothing about its contents, like KotlinPoet's CodeBlock .

This example is a bit convoluted but, for instance, for literals const val foo = 0L this string would be equal to "0L" which one could transform to Long. And just like KSPropertyDeclaration.initializer one could have KSFunctionDeclaration.body and so on. I understand if you think this is out of scope, I just wanted to be clear

[Ting-Yuan Huang]

Thanks for the explanation. That sounds somewhat feasible and useful. Please allow us to think more about it before making any commitments.

[natario1]

Sure - thanks!