Tricks to do "enums"?

[Joal Heagney]

Courageous wrote:

> > "==" works just as well.  Python smart enough to try a pointer
> > compare first.  The code path is almost the same so I doubt there
> > would be much speed gained by using "is".
>
> Well that's cool. The next question is...
>
> Do all string constants which are lexically equivalent obey
> the identity rule? IOW, does the python byte compiler know
> how, upon compilation, to make two seperate instance of
> "joe" point to the same single instance?

I think this is true. Looking up my "Programming Python" book, I tested
this with the 'is' operator.
x = 'joe'
y = x
x is y
        gave 1.
x = 'may'
y = 'may'
x is y
        gave 1.
Trying this on lists
x = ['joe', 'may', 'bob']
y = ['joe', 'may', 'bob']
x is y
        gave 0
y = x
y
        gave ['joe', 'may', 'bob']
x is y
        gave 1.

Joal Heagney/AncientHart