Updated

Now several (4) years later this (almost certainly) can be done; though certainly not with RegEx. I suggest future readers look to @Piotr Dabkowski's answer.. Or some of the other answers. (I don't know having not tried them)

Original Answer

Hm this is a hard one. The definition of a compiler is translates from a higher level language to a lower level language. eg python to machine-code. or java to javascript (google has a rather famous compiler for this somewhere - its' what makes google doc easier to make) Python to javascript compilers abound. technically javascript to python would be a decompiler. (afaik)

I found some speculation about a javascript-python converter here: follow the tread through. it mostly speaks of how it wouldn't be too hard to do. I can't find anything , but that doesn't mean it's no out there.

Regex is not suitable, regex is suitable only for regular languages. programming languages are not normally regular languages. see this