Sqeegie

I'm interested in making custom add-on mods for other mods which don't have APIs. However, I'm wondering if it's possible to use ASM, or Reflection for that matter, on other forge mods instead of vanilla MC code. From what I've read and picked up, the IClassTransformer interface is part of Mojang's launcher. Therefore, is technically separate from Forge/FML. So I'd assume that it'd therefore be possible to transform most classes that are loaded into the JVM, including Forge mods. That being said, I cannot find any examples of someone transforming a mod this way. I don't know if that's because of some copyright issue I'm unaware of, or because it's simply not possible to. I have a little experience transforming MC's code with ASM, however, I'm still quite new to the whole topic. So if someone could point me in the right direction, and if this concept is even possible, could supply me with some examples how it might differ from transforming MC's code (I'd assume you wouldn't be using FML's Loading Plugin), I'd be much obliged to you. - Sqeegie