On 26/09/2011 01:23, Devin Jeanpierre wrote:
Why does it suck?
The gist of what I was saying is that it's possible to define
functions that do this "generically" so that one implementation of
zfill can work with multiple implementations of strings. Having to
reimplement every time when one implementation would do is bothersome
and generally isn't done unless it has to be (thus why mmap lacks a
zfill method). Having to do more work than necessary "sucks", as does
having partial str implementations that don't do everything str does.
Ideally, I would claim that if some interface will have multiple
implementations, it should have as few methods as possible to make
implementation as easy as possible, and move as much as possible
_away_ from methods and into functions that work with arbitrary
implementations of the interface. This minimizes the amount of work
that must be done for implementors and thus makes life better.
[snip]
I would have thought that a better solution would be to specify a
minimal set of methods in an abstract superclass and write the
additional methods using that minimal set.
The concrete string implementations would be descended from the
superclass and would still be able to override the additional methods
with more efficient code were desired, such as in the 'str' class.
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