setProp and Lock messages
ambassador at fourthworld.com
Mon Dec 5 12:39:20 EST 2011
> On Sun, Dec 4, 2011 at 12:10 PM, Richard Gaskin wrote:
>> Here's what the docs say with regard to recursion for setProp:
>> Caution! If a setProp handler in one object's script sets the
>> custom property for a different object, and the first object
>> is in the second object's message path, a runaway recursion
>> will result. For example, if the following handler is in a
>> card script, and you set the "myCustomProperty" of a button
>> on the card, runaway recursion will result:
>> setProp myCustomProperty newValue
>> set the myCustomProperty of the target to newValue + 1
>> -- Because the target is the button, and this handler is in
>> -- the card, the above statement sends another setProp trigger
>> -- to the button.
>> end myCustomProperty
>> To avoid this problem, set the lockMessages property to true
>> before setting the custom property.
> Hi Richard,
> You're right the reference manual does say that. And on the very next
> page, it says:
> "If you use the set command within a setprop handler to set the custom
> property for the current object, no setProp trigger is sent to the
> target object. (This is to avoid runaway recursion, where the setprop
> handler triggers itself)".
> Your example and mine appear to contradict each other so I guess
> there must be two different circumstances described by these two
In my pre-coffee state it seems we're looking at the same thing, with
one small but important distinction:
Recursion will not occur if the setProp handler for a given property
label sets the value of a property using that label, BUT if it calls any
other handler which sets that property then recursion will occur.
Did I miss something?
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