DI.macro.hx

import haxe.macro.Context;
import haxe.macro.Expr;

function build():Array<Field> {
	var fields = Context.getBuildFields();
	for (field in fields) {
		switch [field.name, field.kind] {
			case ["new", FFun(ctor)]:
				var assignExprs = [];
				for (arg in ctor.args) {
					switch (arg.meta) {
						case [{name: "this"}]:
							var fieldName = arg.name;
							assignExprs.push(macro this.$fieldName = $i{arg.name});
						case _:
					}
				}
				var assigns = macro $b{assignExprs};
				ctor.expr = if (ctor.expr == null) assigns else macro { $assigns; ${ctor.expr}; };
			case _:
		}
	}
	return fields;
}

Main.hx

@:build(DI.build())
class Person {
	public var name:String;
	public function new(@this name);
}

function main() {
	var p = new Person("Dan");
	trace(p.name);
}