[jckarter]

The more fundamental mismatch is that they're testing an interpreter (libc's printf implementation) against a compiler (pypy's format string jit). A C++0x or D library that parsed format strings at compile time would likely still beat pypy.

[icebraining]

But Pypy can optimize dynamic strings, while a static compiler can't.

Replace the constant string with argv[1], and run the code: for Pypy, there is no real difference, but the C/C++/D compilers are unable to optimize.

[repsilat]

I think this is still a library problem, not a language problem. "Compiling" a string at runtime for `sprintf` isn't any more difficult than doing it at compile-time, and plenty of regex libraries do very similar things.

Compiling of printf strings isn't done, though, because nobody cares about string performance unless they're writing UNIX command-line utils. If you're writing C you're probably only dealing with strings for (infrequent) IO, spending the vast majority of your time crunching away on pointers and integer types (floats in niche cases). In the end, you're probably only printing something out because someone needs to read it, and how fast can humans read, anyway?

This goes just as much for the printing of floating point numbers. (http://www.serpentine.com/blog/2011/06/29/here-be-dragons-ad...)