Tricks to do "enums"?

[emile at fenx.com]

Watch out for this one.  IRK, this results from auto interning some
strings.

>>> a = "this is a longer string value"
>>> eval("'this is a longer string value' is a")
0
>>> b = "JoeJoeJoeJoeJoeJoeJoeJoeJoeJoeJoeJoeJoe"
>>> eval ("'JoeJoeJoeJoeJoeJoeJoeJoeJoeJoeJoeJoeJoe' is b")
1

There's-an-assumption-at-the-bottom-of-this-I-assume-ly y'rs,

Emily van Sebille
emile at fenx.com

Neil Schemenauer <nascheme at enme.ucalgary.ca> wrote in message
news:<slrn8hcuf4.bh.nascheme at cranky.arctrix.com>...
> Courageous <jkraska1 at san.rr.com> wrote:
> >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?
> 
> A very good question.  I believe that the magic happens when code
> objects are created.  Importing a module causes code objects to
> be created from marshalled code objects.  String constants are
> interned during the creation of new code objects.
> 
> >If so, what are the limits of the byte compiler at merging
> >string identities? For example, will eval() do a prepass
> >through the code and determine identity?
> 
> If my hypothese above is correct then it should work:
> 
>     >>> a = "a"
>     >>> eval("'a' is a")
>     1
> 
> Mmm, support.  Pretending to be a guru is hard work. :)
> 
>     Neil
> 
> -- 
> "God, root, what is difference?" - Pitr
> "God is more forgiving." - Dave Aronson
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>