[Python-Dev] Indexing builtin sequences with objects which supply __int__

[Guido van Rossum]

> There has been some recent interest in the Numeric/numarray community 
> for using array objects as indices
> for builtin sequences.  I know this has come up before, but to make 
> myself clear, the basic idea is to make the
> following work:
> 
> class C:
>     def __int__(self):
>           return 5
> 
> object = C()
> 
> l = "Another feature..."
> 
> print l[object]
> "h"
> 
> Are there any plans (or interest) for developing Python in this direction?

I'm concerned that this will also make floats acceptable as indices
(since they have an __int__ method) and this would cause atrocities
like

print "hello"[3.5]

to work.

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