Experience so far with QML (was Re: dependencies on KJS/KHTML in kdelibs and kdebase-runtime)

Marco Martin notmart at gmail.com
Thu Sep 30 22:33:43 BST 2010

On Tuesday 28 September 2010, Stephen Kelly wrote:
> Aaron J. Seigo wrote:
> > unfortunately, QML is
> > unecessarily difficult to work with due to current implementation
> > decisions that i feel can be best described as "braindamaged" ...
> I'd be interested in reading what makes you say that. I've had difficulties
> with QML too, but sometimes have trouble putting my finger on what exactly
> the problem is.

for us the problems were in the end mainly 2 (i find the language itself 
rather nice instead):
on the guts side, the hiding of the QScriptEngine and the read only-ness of 
the mainobject. this makes impossible to register new types that aren't 
qobjects (and no, for us renouncing to things like KConfig, Q/KIcons etc, and 
with a -clean syntax- is simply not an option) they mess with the engine in 
other interesting ways. the analisys of the problem and how to "solve" it will 
be a good topic for the mobile sprint

on the ui side, besides not agreeing with the existence of 
QDeclarativeItem(that could become justified by the new canvas btw) i think 
it's a mistake that their new layout system forgets the concept of the size 
hint at all, making the creation of flexible user interfaces harder (with a 
bit of effort is not impossible tough, after the last minute changes pre 4.7)
right now one on the mobile can not see the advantage for that, but 
-i would like it to be useful for more than mobile
-i would like to be forced to rewrite the least amount of interface on a 
device that is half a centimeter smaller (yes i now will always require a 
certain amount of customization)

> I think it's a general difficulty in melding the non-declarative parts of
> an application to the declarative parts. The interface between them to get
> state or information from one to the other 'world' is not always obvious.

yes, but i found that after wrapping the mind around the concept comes pretty 
natural, it looks relly like how ui based applications should be developed, it 
really helps detaching the ui from the libraries

> Some of my specific issues with it are quite particular to model-view,
> though with some additional action-related gripes.

yeah, their views are still quite primitive :/

> I think it's here to stay, so it would be good to get a better handle on
> what these issues are.

i'm also hoping it could become -the- way to do graphic interfaces (yeah, not 
specifically -mobile- interfaces) in the future, modulo ironing out the issues 
it still has

Marco Martin

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