Home Original page

[Python-Dev] [NPERS] Re: a feature i'd like to see in python #2: indexing of match objects

Nick Coghlan ncoghlan at gmail.com
Wed Dec 6 13:26:05 CET 2006 
Fredrik Lundh wrote:
> the problem with slicing is that people may 1) expect a slice to return 
> a new object *of the same type* (which opens up a *gigantic* can of 
> worms, both on the implementation level and on the wtf-is-this-thing-
> really level), and 2) expect things like [::-1] to work, which opens up 
> another can of worms.  I prefer the "If the implementation is easy to 
> explain, it may be a good idea." design principle over "can of worms" 
> design principle.

This is a good point - I know I consider "m[0:0] == type(m)()" to be a 
property a well-behaved sequence should preserve. Since match objects can't 
really do that, better not to pretend to be a sequence at all.

With slicing out of the equation, that only leaves the question of whether or 
not len(m) should work. I believe it would be nice for len(m) to be supported, 
so that reversed(m) works along with iter(m).

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
---------------------------------------------------------------
             http://www.boredomandlaziness.org
More information about the Python-Dev mailing list