[Laszlo-dev] documentation for constraints

[P T Withington]

"immediately" is at load time, it is the default, but should only be  
used for constant expressions.

"once" is at init time, it can refer to other nodes that precede this  
one.

"always" is a constraint, it will track changes in the referred to  
values.

Here's a slightly more obvious example:

<canvas>
   <simplelayout spacing="5" />
   <slider id="m" value="25" minvalue="0" maxvalue="100" />
   <text text="$immediately{'immediately: ' + m.value}" />
   <text text="$once{'once: ' + m.value}" />
   <text text="$always{'always: ' + m.value}" />
</canvas>

On 2008-05-22, at 14:53 EDT, Lou Iorio wrote:

> I'm looking at LPP-2037.
>
> I'd like to provide a simple example that illustrates the different  
> values for
> constraints in tags, something like this:
>
> <canvas>
>    <view x="250" width="20" height="20" bgcolor="red" y="$once{m.y}"/>
>    <view x="280" width="20" height="20" bgcolor="blue"  
> y="$immediately{m.y}"/>
>    <view x="310" width="20" height="20" bgcolor="green"  
> y="$always{m.y}"/>
>    <window id="m" x="10" title="Drag me" width="160" height="20"/>
> </canvas>
>
> I don't understand the difference between "once" and "immediately",  
> and this
> example doesn't illustrate the difference.
>
> What's the difference, and is there a better example I can use?
>
> Thanks,
>
> Lou
>
>