[PyQt] Re: PyQt4 and Python 3.0

[Giovanni Bajo]

On 10/6/2008 8:42 PM, Phil Thompson wrote:
> On Mon, 06 Oct 2008 19:42:26 +0200, Giovanni Bajo <rasky at develer.com>
> wrote:
>> On 10/6/2008 7:27 PM, Joshua Kugler wrote:
>>> Phil Thompson wrote:
>>>
>>>> On Fri, 3 Oct 2008 17:11:19 +0200, Detlev Offenbach
>>>> <detlev at die-offenbachs.de> wrote:
>>>>> Hi,
>>>>>
>>>>> will there be PyQt4 support for Python 3.0 once it goes final?
>>>> Not straight away. I will take the opportunity to break backwards
>>>> compatibility (eg. removing QVariant, QString, QChar, QByteArray etc),
>>>> and
>>>> those changes will be made over a period of time. So it may be a while
>>>> before the API is stable enough for anything other than playing.
>>> Before you do that, please take into consideration Guido's advice:
>>>
>>> "Don't change your APIs incompatibly when porting to Py3k."
>>>
>>> http://www.artima.com/weblogs/viewpost.jsp?thread=227041
>> I think the main collision here is that Guido is trying to help people 
>> porting their applications to Python 3.0, while Phil seems to think that 
>> it's better to rewrite them.
>>
>> IMO, PyQt shouldn't force its users to rewrite their code, especially 
>> *not* tieing this to someone else's schedule (Qt4 release, Python 3 
>> release). If an application grows unmaintainable, it will get eventually 
>> rewritten but only when the programmer thinks so.
>>
>> Putting incompatible changes into PyQt and then telling people "*now* 
>> it's time to rewrite" doesn't seem a good path forward to me.
>>
>> If there's agreement that we need to break backward compatibility on 
>> PyQt (by changing the way QString or QVariant are mapped), I think it's 
>> better to do so *independently* from any other changes (eg: Python 3).
> 
> I'm quite happy to consider that if it can be done without confusing the
> hell out of everyone.
> 
> The only way to allow two incompatible versions of PyQt to sit in the same
> Python installation (that would be a requirement) would be to have the new
> version be PyQt5.
> 
> Is that a good idea?

Looks like it, until Qt5 is out ;)

Multi-version installs are possible without changing the package name, 
in the same way that .egg/setuputils does: using a .pth file to select a 
given version at startup time (site.py).

wxPython has been doing it for ages to eg. switch between ANSI and 
Unicode version, or keeping several version in parallel and let the user 
change the current one.
-- 
Giovanni Bajo
Develer S.r.l.
http://www.develer.com