[PyQt] More pythonic API

[Phil Thompson]

On Sat, 1 Aug 2009 11:46:59 +0200, Florian Friesdorf <flo at chaoflow.net>
wrote:
> On Wed, Jul 29, 2009 at 02:54:51PM +0100, Phil Thompson wrote:
>> On Wed, 29 Jul 2009 14:44:54 +0200, Florian Friesdorf <flo at chaoflow.net>
>> wrote:
>> > Hello,
>> > 
>> > Based on a longer python history and no Qt experience, I'm just
>> > starting
>> > with PyQt. My enthusiasm is a bit slowed down by the non-pythonic API:
>> > 
>> > a = QAction()
>> > a.setEnabled(True)
>> > enabled = a.isEnabled()
>> > 
>> > setting = QSettings()
>> > filename = 'some.file'
>> > qfilename = QVariant(QString(filename))
>> > settings.setValue("LastFile", qfilename)
>> > filename = settings.value("LastFile").toString()
>> > 
>> > Preferably these would look something like:
>> > 
>> > a = QAction()
>> > a.enabled = True
>> > enabled = a.enabled
>> 
>> This is fairly easy to implement but would be an incompatible change.
> 
> I wouldn't like having my code rely on a specially built PyQt. Is it
> possible to generate these bindings as extra add-on modules?

They'd have to be replacements not add ons.

>> > settings = QSettings()
>> > filename = 'some.file'
>> 
>> You can do this now. With the current version of PyQt you never need to
>> explicitly create a QVariant. In the next version of PyQt (v4.6)
QVariant
>> and QString will be (optionally) gone completely.
> 
> great!
> 
>> > settings["LastFile"] = filename
>> > filename = settings["LastFile"]
>> > 
>> > One thing here is the implicit use of __getitem__() and __setitem__()
>> > instead of two different explicit functions. The other is a
translation
>> > of QVariant to string and vice versa.
>> > 
>> > - Are there any wrappers available that translate to a more
>> >   pythonic API, i.e. not just direct bindings?
>> 
>> Not yet - see below.
>> 
>> > - Could SIP be extended to create these, i.e. would it be
>> >   sane to have SIP extended to create these?
>> 
>> It can be done, but not automatically. You would need to implement each
>> Pythonic feature with (a small amount of) handwritten code.
> 
> I'd like to take a look on it. Can you give me some pointers?

Read the SIP documentation. You'd be implementing __getitem__ etc with
%MethodCode.

>> > - Are there any plans to work towards a more pythonic API?
>> > - Am I the only one getting cognitive dissonance when programming with
>> >   the less pythonic versions?
>> 
>> I think that tends to be counter-balanced by the fact that Qt is very
>> consistent in its API (therefore predictable) and the documentation is
>> clear and easy to use.
>> 
>> That said, I am currently working on a declarative layer on top of PyQt.
>> The purpose is *not* to have an alternative API, but to have a
>> complementary one that is good for the more boring parts of GUI design
>> (forms, dialogs etc).
> 
> that sounds great!
> 
> thank you very much!
> florian

Phil