On Samstag, 4. Oktober 2008, Phil Thompson wrote: > On Fri, 03 Oct 2008 16:45:12 -0700, Glenn Linderman <[EMAIL PROTECTED]> > > wrote: > > On approximately 10/3/2008 4:25 PM, came the following characters from > > > > the keyboard of Phil Thompson: > >> Personally I think "compatibility wrappers" are a waste of time and > >> effort. > >> There are times when you really should rewrite your application (and I > >> don't care how big it is). PyQt4 is a complete rewrite of PyQt3, SIP5 > >> will > >> not share any code with SIP4. > > > > Interesting philosophy. Some truth there. But then it is a big job to > > do a rewrite, and someone else's release schedule isn't always the right > > time. > > You have a potential problem if one customer wants your app for Py2 and > another for Py3. In reality I don't see that as a major problem as paying > customers are going to be the most conservative. I think it will be a while > before Py3 becomes mainstream. > > >> Major transitions (Qt3 => Qt4, Python2 => Python3) should be considered > >> as > >> opportunities for rewrites. They should not be treated as "how can I get > >> from one to the other with as few changes as possible". > > > > If the application was old, I might agree. But here I am, thinking > > about, and starting to code, a brand new application. > > > >> Therefore, to answer your specific question, if you need to deploy your > >> application within 6 months (as a minimum) then write for Python2. If > > you > > >> do then don't bother trying to write it with Python3 in mind. By the > > time > > >> you get to the point when you want a Python3 version you will have > >> realised > >> how badly you wrote it in the first place that you will want to rewrite > >> it > >> anyway. > > > > So say I wish to deploy in 8 months (the reality is, it will be deployed > > when it is ready, if not sooner, and that depends on how things go with > > some other projects also)... I'd like to avoid deploying it twice in > > succession on different platforms within a couple months... and even if > > it was deployed in 4 months, I'd hardly know what to rewrite by then. > > Unless your have specific customer demands as I mentioned above, then its > up to you what you deploy. > > >> On the other hand, if you did write it correctly in the first place > >> (something I've never managed) PyQt4 for Python2 will be maintained for > >> several years - certainly while new versions of Python2 are released. > > > > So this implies, just build it for Python 2 and deploy it, and if it > > works well enough, leave it there until I figure out what rewrites are > > necessary. Certainly possible, but I'm already tired of putting "u" in > > front of my string constants > > Which you don't need to do. > > > and of converting from QString back to > > unicode... > > ...and avoiding that will be a benefit of moving to PyQt for Py3. It's up > to you. > > Obviously you can take sensible steps when designing your app to minimise > the changes - keep your GUI code separate from your models and business > logic, add some "compatibility wrapper" stuff that makes sense in the > context of your own app. > > What I will try and do - probably via the wiki - is to document what the > incompatibilities will be (though it will be a moving target) so that > people can try and write for both Py2 and Py3 if that's appropriate for > their app.
How about creating a tool (script) that converts old code to new code, doing the straight forward conversions automatically and marks the more complex conversions. Something like the promised py2to3 script (maybe pyqt4to5)? Detlev -- Detlev Offenbach [EMAIL PROTECTED] _______________________________________________ PyQt mailing list PyQt@riverbankcomputing.com http://www.riverbankcomputing.com/mailman/listinfo/pyqt
