Avoiding recursion with a setProp handler

[Klaus Major]

Hi David,

> MC 2.5's help stack says that "when you set an object's property from 
> within a setprop handler, setprop messages are not sent."  Is this 
> true?
>
> Here's my handler:
>
> setProp beenChanged whether
>   put the short date  into fld 3
     ###set the beenChanged of this stack to whether -- (without this, 
the setProp handler intercepts the calling command, and the property is 
not set)
       pass setprop ## ;-)
> end setProp

> When some other handler commands "set the beenChanged of this stack to 
> true", my setProp handler gets called.  But when I watch the message 
> watcher, it appears that the second line of my setProp handler is 
> recursively calling the setProp handler, and I get a "recursion limit 
> reached" error.
>
> I realize that I could easily avoid resorting to a setProp handler at 
> all, but I was tempted by the ease with which I thought it would allow 
> me to add some behavior I had not thought of when I first wrote a lot 
> of handlers that "set the beenChanged of this stack."  Having come 
> this far, I would like to understand how to use setProp properly.

See above, simply "pass"ing the "setprop" will finally SET THIS PROP :-)

Hope this helps.

> Many thanks.
>
> David Epstein

Best from germany

Klaus Major
klaus at major-k.de
http://www.major-k.de