[the_mitsuhiko]

> PyPy is still significantly faster than CPython while (afaik) allowing that sort of stuff to go on

First of all that's only true when it managed to jit the code, secondly only until you try to do any of those slow things. For instance the C ABI emulation they have both cannot support all of CPython and wrecks performance. The same is true if you try to do fancy things with sys._getframe which a lot of code does in the wild (eg: all of logging).

In addition PyPy has to do a lot of special casing for all the crazy things CPython does. I recommend looking into the amount of engineering that went into it.

[overgard]

Yeah, but most code doesn't use things like sys.getframe? I don't see the problem here. You can choose whether those features are worth the speed penalty or not.

And yeah the C ABI is slow, but that's true of practically every language. Again, it's a choice of if you use those things or not. That doesn't devalue making other parts of the language faster.