I can't remember for sure whether Toolpack's revision control component actually operated with ASTs, but I think it did. Certainly there was a semantic diff an

I can't remember for sure whether Toolpack's revision control component actually operated with ASTs, but I think it did. Certainly there was a semantic diff and patch. (Toolpack was quite an advanced a Fortran77 engineering tool set from the 1980s.) I don't know how general they could be, but darcs can have different patch types. However, the only extra one implemented, as far as I know, is token replacement.