> Haxe is the de facto king of the compile-to-everything space.
Indeed, I remember stumbling across it years ago while looking for a way to develop Flash games without Adobe Flash Professional. I never got around to actually try it but I keep seeing it every now and then, even saw a couple of books about it in a physical bookstore some years ago. It was the first thing that popped to mind for me as well when I saw that OP title mentioned write code in multiple languages at the same time.
Indeed, I remember stumbling across it years ago while looking for a way to develop Flash games without Adobe Flash Professional. I never got around to actually try it but I keep seeing it every now and then, even saw a couple of books about it in a physical bookstore some years ago. It was the first thing that popped to mind for me as well when I saw that OP title mentioned write code in multiple languages at the same time.