[Python-Dev] Make _strptime only time.strptime implementation?

[Brett C.]

Guido van Rossum wrote:
>>>[Brett]
>>>
>>>
>>>>>>I got a single email from someone asking me to change the
>>>>>>functionality so that it would raise an exception if part of the
>>>>>>input string was not parsed.
>>>>>
>>>[Guido van Rossum]
>>>
>>>
>>>>>That sounds like a good idea on the face of it.  Or will this break
>>>>>existing code?
>>>
>>>
>>>[Brett]
>>>
>>>
>>>>Maybe.  If they depend on some specific behavior on a platform that offers
>>>>it, then yes, there could be issues.  But since the docs are so vague if
>>>>it does break code it will most likely be because someone didn't follow
>>>>the warnings in the spec.
>>>
>>>
>>>If you add some flag to control this behavior, defaulting to strict,
>>>then at least people who rely on the old (non-strict) behavior can use
>>>the flag rather than redesign their application.
>>>
>>
>>But the problem is that I have no idea what the old behavior is.  Since 
>>the spec is so vague and open I have no clue what all the various libc 
>>versions do.  I have just been patching strptime the best I can to 
>>handle strange edge cases that pop up and work as people like Kevin need 
>>it to.
> 
> 
> OK.  Maybe I misunderstood (I've now got to admit that I've never
> tried strptime myself).  From your initial message (still quoted
> above) I thought that it was a simple case of strptime parsing as much
> as it could and then giving up (sort of like sscanf), and that the
> suggestion you received was to make it insist on parsing everything or
> fail.  I still think that would be a clear improvement.  But if the
> original situation wasn't as clear-cut, maybe I should have stayed out
> of this...
> 

I wasn't clear enough.  I already patched strptime to raise an error if 
there is anything left that was not parsed (my first CVS checkin 
actually); this functionality is already there.  So I think we just 
talked ourselves in a circle.  =)

> 
>>Unless you are suggesting a flag that when set controls whether the 
>>Python version or a libc version if available is used, which I guess 
>>could work as a transition to get people to move over.  Is this what you 
>>are getting at, Guido?  And if it is, do you want it at the function or 
>>module level?  I say function, but that is because it would be easier to 
>>code.  =)
> 
> 
> No, that's not what I was going for at all -- I think that would be a
> mistake that woud just cause people to worry needlessly about which
> strptime version they should use.
> 

Well, now that I think we have the whole strict parsing cleared up, I 
assume we don't need this anymore.  Is there any other worries?

-Brett