Shane Hathaway wrote: <snip>
> > Please could somebody explain to us non-CS people why PyPy could > > have speed features CPython can't have? > > The idea is to shift more of the responsibility to optimize code from > the human to the computer. Since C code is at a low level, the computer > can only infer low level intent and thus perform low level > optimizations. Humans optimize C by making thousands of speed-oriented > decisions directly in the code. Python code is at a much higher level, > which should enable the computer to discover more of the programmer's > intent and perform deep optimizations. > > In the end, the computer's automated optimization could turn out better > than a human's manual optimization. Thus, by expressing the Python > interpreter in a high level manner, PyPy is a first step toward deep > optimizations that aren't possible to automate in C. I am less optimistic but hope I am wrong :). C++ is a higher level language than C, but it's not clear to me that compilers are able to optimize C++ code using higher-level features such as the Standard Library so that they run as fast as the equivalent C code. OTOH, some C++ experts have advocated template metaprogramming as a way of speeding up programs. I wonder how widely this technique is used. Fortran 95 is a considerably higher level language than Fortran 77, but I get the impression from comp.lang.fortran that it is harder to optimize. Fortran compilers compete in a performance-driven market, and AFAIK they are written in C. -- http://mail.python.org/mailman/listinfo/python-list
