Why has python3 been created as a seperate language where there is still python2.7 ?

[Stefan Behnel]

Serhiy Storchaka, 28.06.2012 07:36:
> On 28.06.12 00:14, Terry Reedy wrote:
>> Another prediction: people who code Python without reading the manual,
>> at least not for new features, will learn about 'u' somehow (such as by
>> reading this list) and may do either of the following, both of which are
>> bad.
>>
>> 1. They will confuse themselves by thinking that 'u' actually means
>> somethings. They may then confuse others by writing about its supposed
>> meaning. This might get amusing.
>>
>> 2. They will use 'u' in Python 3 only code, thereby making it
>> incompatible with 3.2-, even if it otherwise would not be.
>>
>> These two actions will reinforce each other.
> 
> Yes, this is what I mean. I can even make a prediction: in just 5 years, as
> this feature would be banned in a decent society. The authors of the books
> will be strongly advise not to use it, and in software companies 'u' will
> be prohibited in coding style. But get rid of this will be difficult.

Once Py2.7 is out of maintenance, we can deprecate that feature in one
release and start warning about it in the next one. You're then free to use
the corresponding 2to3 fixer to get it back out of your code with a single
patch.

Stefan