[Python-Dev] bytes.from_hex() [Was: PEP 332 revival in coordination with pep 349?]

["Martin v. Löwis"]

M.-A. Lemburg wrote:
>>>True. However, note that the .encode()/.decode() methods on
>>>strings and Unicode narrow down the possible return types.
>>>The corresponding .bytes methods should only allow bytes and
>>>Unicode.
>>
>>I forgot that: what is the rationale for that restriction?
> 
> 
> To assure that only those types can be returned from those
> methods, ie. instances of basestring, which in return permits
> type inference for those methods.

Hmm. So it for type inference????
Where is that documented?

This looks pretty inconsistent. Either codecs can give arbitrary
return types, then .encode/.decode should also be allowed to
give arbitrary return types, or codecs should be restricted.
What's the point of first allowing a wide interface, and then
narrowing it?

Also, if type inference is the goal, what is the point in allowing
two result types?

Regards,
Martin