[Laszlo-dev] Initialization difference between swf and dhtml

[Henry Minsky]

Nope I was wrong, text centering did break in some button (but not
some other one!)


On 11/28/06, Henry Minsky <henry.minsky at gmail.com> wrote:
> Hey I just tried moving that new LzDelegate out of the loop and it
> didn't break centering
> of text in the button component. I wonder if we fixed that when we
> fixed the order of setters or something.
>
> I think we should bite the bullet and normalize the order of
> everything, otherwise we'll
> be like those guys at Microsoft, crushed under the weight of backward
> compatibility
> with every version since Windows 3.1 or something.
>
>
> On 11/28/06, P T Withington <ptw at openlaszlo.org> wrote:
> > You are 100% right Jim, but this will break a lot of apps that, right
> > now, happen to 'just work'.  Please see the note at line 1124 in
> > LzNode.lzs for a glimpse into what is at stake here.
> >
> > I am all for making this change, but there will be fallout...  OTOH,
> > if we _don't_ have to preserve the accidental behavior of
> > constraints, we open up a whole raft of optimization possibilities
> > that have been precluded by the requirement of backward compatibility.
> >
> > On 2006-11-28, at 20:31 EST, Jim Grandy wrote:
> >
> > > Agreed, but constraint satisfaction is too complex to enforce
> > > lexical ordering over. It's also too hard to understand what's
> > > going on if the two aren't in separate phases -- this is the
> > > mistake in the current system, which leads to lots of constraint
> > > satisfaction over uninitialized attributes. Plus in theory no
> > > predefined order is necessary for constraints -- you just start
> > > with one and keep going until it all settles down. I think this
> > > would be clean:
> > >
> > > - initialize own class' attributes to constants, first by class and
> > > then by lexical order
> > > - initialize instance's unique attribute to constants, in lexical
> > > order
> > > - run all all attribute constraints, in undefined order
> > >
> > > jim
> > >
> > > On Nov 28, 2006, at 3:39 PM, Henry Minsky wrote:
> > >
> > >> Note that implementing the lexical ordering is likely to break a
> > >> couple of legacy apps
> > >> that depend implicitly on the current ordering. Of course, several
> > >> DHTML versions are
> > >> already broken due to the different order now (I think I fudged a
> > >> couple of constraints in the amazon app to work around one case
> > >> already, with height initialization on a component) , so it's not
> > >> really a reason to try to preserve existing behavior.
> > >>
> > >>
> > >>
> > >> On 11/28/06, Jim Grandy <jgrandy at openlaszlo.org> wrote:
> > >>>
> > >>> On Nov 28, 2006, at 2:33 PM, Adam Wolff wrote:
> > >>>
> > >>> > On Nov 28, Don Hopkins wrote:
> > >>> > [snip]
> > >>> >> I think it's pretty important to give class programmers the
> > >>> >> ability to
> > >>> >> control the order in which the attributes are initialized at
> > >>> class
> > >>> >> declaration time.  It's also sometimes useful for object users to
> > >>> >> control the initialization order at object instantiation time,
> > >>> but
> > >>> >> usually they shouldn't have to care, or be required to
> > >>> understand the
> > >>> >> inner workings.
> > >>> > Agree that this is appealing and sensible, but I don't think it's
> > >>> > practically possible. As a class user, I can say
> > >>> >
> > >>> >     <yourclass attr1="$once{ a }" attr2="$immediately{ b }"/>
> > >>> >
> > >>> > and then attr2 will be set before attr1 regardless of what you
> > >>> > might want
> > >>> > as the class implementor.
> > >>> >
> > >>> > A
> > >>>
> > >>> I think constraint satisfaction has to be a separate phase from
> > >>> attribute initialization, and really needs to have indeterminate
> > >>> execution order to preserve optimization/implementation flexibility.
> > >>> Attribute initialization to a constant value really needs lexical
> > >>> order, by class. The two shoud really be separate.
> > >>>
> > >>> jim
> > >>>
> > >>>
> > >>
> > >>
> > >> --
> > >> Henry Minsky
> > >> Software Architect
> > >> hminsky at laszlosystems.com
> > >
> >
> >
>
>
> --
> Henry Minsky
> Software Architect
> hminsky at laszlosystems.com
>


-- 
Henry Minsky
Software Architect
hminsky at laszlosystems.com