> However, they cannot stop anyone writing the plugin that exposes the AST in such a way to be usable by proprietary programs. I'm not entire sure they couldn'

> However, they cannot stop anyone writing the plugin that exposes the AST in such a way to be usable by proprietary programs. I'm not entire sure they couldn't... It really comes down to the definition of a derivative work. It's often assumed that a process boundary would somehow raise some legally impenetrable wall between works, but I'm not sure a court would necessarily agree.