Simon Knight wrote:

> "Is there some simple way that an openCard handler can branch based on
> what card it is coming from?"
>
> My solution would be to give each card a customprop named say
> “uCalledBy".  Then when the app changes cards I set this prop e.g.
>
> Set the uCalledBy of Card 42 to “HitchHikers”
> Go to Card 42
>
> Then in Card 42 ’s  opencard or anywhere else
>
> If the uCalledBy of me is “HitchHikers” then
>    answer “Where is your towel?”
> end if

Custom properties are an excellent option when both of these requirements are met:

1. The data is most meaningfully expressed when bound to a specific
   object.

2. The data benefits from persistence.

In the scenario at hand, #1 is well met, but #2 may be problematic.

For example, if you happen to save the stack while working on it (who doesn't?) then you'll have property values in place that may not be relevant to the next runtime session.

This would require that you add a handler to clear those properties on startup, or some other useful entry point for execution, in addition to adding the code above.

When you find yourself writing handlers to clean up after other handlers you've written, it may be time to reconsider the original premise.


FWIW Jacque's solution seems the most with-the-grain one yet, using the function designed for this purpose:

> Look at the recentCards. Line 2 is the card you came from.

--
 Richard Gaskin
 Fourth World Systems
 Software Design and Development for the Desktop, Mobile, and the Web
 ____________________________________________________________________
 [email protected]                http://www.FourthWorld.com

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