[Python-Dev] Alternative implementation of interning, take 2

[Guido van Rossum]

> What I do need and rely on is the fact that the
> Python compiler interns all constant strings and identifiers in
> Python programs. This makes switching like so:
> 
> if a == 'x':
> elif a == 'y':
> else:
> 
> also work like this (only faster):
> 
> if a is 'x':
> elif a is 'y':
> else:
> 
> provided that 'a' only uses interned strings.

Yuck.  This is an implementation detail.  While it's unlikely to go
away in Python 2.0, please don't rely on this in portable Python.

--Guido van Rossum (home page: http://www.python.org/~guido/)