[Python-Dev] Interning string subtype instances

[Josiah Carlson]

Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
> 
> Josiah Carlson wrote:
> > def intern(st):
> >     ...
> > 
> > If I remember the implementation of intern correctly, that's more or
> > less what happens under the covers.
> 
> That doesn't quite give you everything that real interning
> does, though. The string comparison method knows when both
> strings are interned, so it can compare them quickly
> whether they are equal or not. Your version could detect
> equal strings quickly, but not unequal strings.

Assuming that dictionaries and the hash algorithm for strings is not
hopelessly broken, I believe that one discovers quite quickly when two
strings are not equal.  Simple testing seems to confirm this, but I
didn't work too hard to disprove it either.

 - Josiah