On Sunday, April 9, 2017 at 4:05:57 AM UTC-5, Chris Angelico wrote: > On Sun, Apr 9, 2017 at 5:39 PM, Steven D'Aprano <st...@pearwood.info> wrote:
> > Even better would be if the compiler was smart enough to > > use the optimized, fast runtime when the dynamic features > > aren't used, and fall back on a slower implementation only > > when needed to support the more dynamic features. > > Yes. As long as it can know when the more dynamic features > are being used - and that's the hard part. Remember, as > soon as you have a single class implemented in Python, it > could have a method injected into it without your > knowledge. Can you detect that statically, or can you use > the versioning of __dict__ to notice that something's been > broken? What makes you fall back to the default > implementation? And all that sleuthing is slow as hell! The simple solution is to use a declaration (aka: "strict" in JS) instead. The programmer should be intelligent enough to know whether the code is written in an "optimized manner", or not. > The problem is the same thing that gives Python a lot of > its beauty: that there's very little difference between > built-in types and user-defined types. In CPython, types > implemented in C are immutable, but other than that, > they're basically the same thing as anything you make, and > you can inspect them and stuff: > > >>> int.__add__(5, 7) > 12 Who the hell wants to call dunder methods? Self-flagellate much? > Personally, I think that would be a far better avenue to go > down. I'm not sure it would be possible to retrofit this to > Python (for example, there are guarantees about object > identity that apply to *all objects*), but making the core > immutable types into value-only non-objects wouldn't break > a lot of code, and might provide for some significant > performance improvements to string manipulation and > arithmetic operations. But at some point, it's not really > Python any more. Well, go tell that to the type-hints shills! -- https://mail.python.org/mailman/listinfo/python-list
