Its quite clear using the sendEvent method, like you illustrate, and
although i like One Way to Do things, it reads right! So on that score
carry on. On another angle, what if i get a name from a server source
and the name is the same, but other values are different, and because
of that other operations don't occur? I think it's a iffy move. If you
do change it, it's certainly not the end of the world.
.j
On Apr 25, 2009, at 7:21 PM, Henry Minsky wrote:
It seems to me that in your example, you really want to send an
event, and setting the attribute is one step removed from that. So
maybe the most
clear way to implement that would be to call sendEvent directly
<method name="update">
canvas.onupdate.sendEvent( true);
</method>
On Sat, Apr 25, 2009 at 6:46 PM, jamesr <[email protected]> wrote:
On Fri, Apr 17, 2009 at 6:36 PM, P T Withington <[email protected]> wrote:
I'm working on http://jira.openlaszlo.org/jira/browse/LPP-8058 to
reduce the number of extraneous events sent by implementing the
following optimization:
If an attribute is constrained, and the values the constraint
depends on change, but the result of the constraint does _not_
change, then the attribute will not be updated (to the identical
value) and, more importantly, no `on` event will be sent. The
change can be demonstrated by considering the following:
<canvas layout="axis: x; spacing: 5" debug="true">
<attribute name="jay" value="2" />
<handler name="onjay">Debug.info("onjay")</handler>
<attribute name="kay" value="4" />
<handler name="onkay">Debug.info("onkay")</handler>
<attribute name="jaykay" value="${jay*kay}" />
<handler name="onjaykay">
Debug.info("onjaykay: %d * %d = %d", jay, kay, jaykay);
</handler>
<button onclick="canvas.setAttribute('jay', canvas.jay)">Same</
button>
<button onclick="canvas.setAttribute('jay', canvas.jay +
1)">Different</button>
</canvas>
In the current system, setting `jay` will _always_ cause `jaykay` to
be updated, and for there to be an `onjaykay` event. In the
proposed change, setting `jay` to the same value, will cause an
`onjay` event, but the constraint on `jaykay` will have the same
result, so `jaykay` will _not_ be updated and there will be _no_
`onjaykay` event sent.
Comments? Questions?
I use handlers to fire functionality without actually changing any
values. An example would be
<canvas>
<attribute name="update" type="boolean" value="false"/>
<...>
<handler name="onupdate" reference="canvas">
//do something
</handler>
</...>
<canvas>
<method name="update">
canvas.setAttribute('update', true);
</method>
where i expect the update handlers to get run on true regardless of
whether they were already true before. This change would require
that i set update to false after such an event. In my own runtime, i
include a "touch" method which allows me to fire an event without
having to set an explicit value, just for these type of delegate
networks. I would toss in my two cents by saying that it would be
nice to have one or the other available to me.
there might be other methods to accomplish the same thing - i'm just
pointing out a pattern that my code depends on, currently
-james
--
Henry Minsky
Software Architect
[email protected]
