[Python-Dev] Core projects: 3to2

[Terry Reedy]

Antoine Pitrou wrote:
> Terry Reedy <tjreedy <at> udel.edu> writes:
>> Some of the people who need to support both late 2.x and 3.x would 
>> prefer to write 3.x code and backport.  The OP of a current python-list 
>> thread asked whether there was any way to write something like
>>
>> 	@alias('__nonzero__')
>> 	def __bool__(self): return True
> 
> How about simply:
>     __nonzero__ = __bool__
> 
>> I believe my own 3.0 code will mainly also need
>> print() to print statement
> 
> If this is only about supporting "late 2.x" (i.e., 2.6 and upwards), you can
> already write:

People often do not specify.  I suspect some are thinking back to 2.5, 
but that will change in the future.

> from __future__ import print_function

I was not aware of that.  Would be ok for my current project which has 
print isolated in a few modules, at least so far.

>> except e as a to 2.x version
> 
> Works in 2.6.

Did not know that.  Perhaps a 3 to 2.6+ guide would help.
> 
>> class C() to class C(object)

Part of the reason to move to 3.0 is to not have to do that.
> 
> __metaclass__ = type
> 
> Now I'm not saying that all 3.0 code will work in 2.6 with such simple
> precautions, far from it!

tjr