"faster and...more maintainable"
TransCoder...could help port a project from Python to C++...It may make the code faster and also more maintainable since code written in strongly-typed languages can be easier to understand.
Get real. Anyone who's maintained human-written code will have experienced wanting to shake its author by the throat, because typical source code is of abysmal quality. We're a long way from any machine that will improve on that. So don't ask me to work on TransCode's output, because it will have to do a lot more than change x=2 to int x=2 (even if it gets that right) to compensate for the general mess with which it will likely start and to which it can only add.
As for speed, there has been very little code worth speeding up for the last 40 years or more. The overwhelming problem, then and still now, is how to write clear and reliable source that reflects the requirements accurately. Making code faster is appropriate in niche cases, which most of us need rarely to address.
Biting the hand that feeds IT
