Front Scripts Issue

[Richard Gaskin]

Peter Haworth wrote:

> I have a number of message handers set up as front scripts to carry  
> out standard processes on any cards in my stack,things like  
> closeField, selectionChanged, etc.  The problem is it appears that  
> these scripts are being executed when the events they handle come from  
> the Rev IDE, which causes some pretty severe problems.  I'm quite  
> surprised that the IDE would pass it's events to my front scripts  
> since they are part of my application not the IDE but be that as it  
> may, I need to find a way around this issue.
> 
> I've made execution of my front script code dependant on the current  
> tool being the pointer but that doesn't help when I'm in edit mode to  
> modify cards or scripts.
> 
> I guess my question is whether there is a better place to put these  
> scripts in the message path to avoid them being  called from the IDE,  
> or if there is some reliable way to check if the messages they receive  
> are coming from my application stacks and not the IDE.

Forgive the seeming tautology, but put your handlers where you need 'em. ;)

FrontScript are handy, but they're available for a very specific 
purpose:  to catch ALL messages BEFORE objects get them.

If you need both of those conditions met, frontScripts will be hard to 
beat.  But for everything else there are many options:

- mainStack script:  that way you'll only get the messages sent to your 
main stack or substacks

- use "if" to differentiate whether to handle message or not, looking 
for something like

    if the effective filename of this stack is "MyStack" then...

- behaviors:  assigning a behavior script to your objects will let you 
handle those messages only for the objects to which the behavior is 
attached.

This article may be helpful:

Extending the Runtime Revolution Message Path:
An introduction to using Libraries, FrontScripts, BackScripts and 
Behaviors in Runtime Revolution's RevTalk Programming Language

<http://www.fourthworld.com/embassy/articles/revolution_message_path.html>

Note for Mark Wieder:  Yes, I finally got around to adding mention of 
"dispatch" there. :)

--
  Richard Gaskin
  Fourth World
  Rev training and consulting: http://www.fourthworld.com
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