[Python-Dev] Allowing u.encode() to return non-strings

[M.-A. Lemburg]

Jeremy Hylton wrote:
> On Thu, 17 Jun 2004 08:43:15 -0700, Guido van Rossum <guido at python.org> wrote:
> 
>>The issue is that currently the type inferencer can know that the
>>return type of u.encode(s) is 'unicode', assuming u's type is
>>'unicode'.  But with the proposed change, the return type will depend
>>on the *value* of s, and I don't know how easy it is for the type
>>inferencers to handle that case -- likely, a type inferencer will have
>>to give up and say it returns 'object'.
> 
> 
> Who cares about the type inference <0.2 wink>.  It's harder for the
> reader of the program to understand if encode() returns a different
> type.  Would there be some common property that all encode() return
> values would share?  Can't think of one myself.

In my reply to Guido's post I mentioned that it would be reasonable
to limit the number of types to 2 (basically types.StringTypes and
subclasses).

We could then add two new helpers codecs.encode() and .decode()
to do more general codec work without this type restriction.

-- 
Marc-Andre Lemburg
eGenix.com

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