Is there a way of getting the names of all subclasses - haxe

Question

I want to get the names of all subclasses of a base class. From that I want to #:build an enum where every entry is the name of a class. Is this possible?

Answer 1

Here is the code. The order of macro executions is undefined, as specified in documentation.
[AutoBuildingMacro.hx]
import haxe.macro.Context;
import haxe.macro.Expr;
final mapofnames = new Map<String,Array<String>>();
class AutoBuildingMacro {
public static macro function fromBaseClass(base):Array<Field> {
var parent = haxe.macro.ExprTools.toString(base);
var names = mapofnames[parent];
if ( names == null ) {
names = new Array<String>();
mapofnames[parent] = names;
}
names.push(Context.getLocalClass().toString());
trace(mapofnames);
return null;
}
}
[Main.hx]
import AutoBuildingMacro;
class Main {
static public function main() {}
}
#:autoBuild(AutoBuildingMacro.fromBaseClass(Parent))
class Parent {
}
class Child1 extends Parent {
}
class Child2 extends Parent {
}
class Child3 extends Child2 {
}
Output:
AutoBuildingMacro.hx:15: {Parent => [Child2]}
AutoBuildingMacro.hx:15: {Parent => [Child2,Child3]}
AutoBuildingMacro.hx:15: {Parent => [Child2,Child3,Child1]}

Answer 2

You are looking for auto-build macro feature https://haxe.org/manual/macro-auto-build.html
And then enum building https://haxe.org/manual/macro-enum-building.html

Answer 3

I wrote a library called compiletime that has this feature:
// Returns a list of all the classes that inherit MySuperClass, no matter what package
CompileTime.getAllClasses(MySuperClass);
The approach I took worked around the build order problem by using the Context.onGenerate hook to build an array of matching classes at the end of compilation (rather than as each class is compiled) and add the array to “metadata”, which can still be modified in the “onGenerate” step. I then use this metadata in a separate runtime class to get the array of classes at runtime.