A question about openCard

David Epstein dfepstein at comcast.net
Sat Jun 8 09:13:25 EDT 2019

Several people gave helpful replies to my question, including pointing out that this is a case of “resumeStack”, not “openCard”:

Is there some simple way that an openCard handler can branch based on what card it is coming from?

When a user goes to a different card in a stack, or to a different stack, I use an “openCard” handler to set things up.  But I do not want those actions taken if the user is merely “returning” to a card after using a palette tool, or after a palette tool has been opened.

Jacqueline Gay suggested using the “recentCards” to determine what card the user is coming from.  So I wrote this handler:

function resumedTheSameCard
  -- call this in a "resumeStack" handler.
  -- returns true if palette "tTools" has just been active and the resumeStack message was received by the same card that had been active when that palette was activated.
  -- returns false if we are coming from a different card, either directly or with a palette activation in between.
  get the recentCards
  if the long id of stack "tTools" is not in line 2 of it then return false -- nb should work even if palette "tTools" stack has several cards
  return line 1 of it = line 3 of it
end resumedTheSameCard

But this does not work.  When I debug, I see that line 2 of the recentCards does not refer to a card on my palette stack (“tTools”); it refers instead to a card in the stack “Execution Contexts”.

Why is that LiveCode system stack appearing in the recentCards, and why is my palette not appearing there?

Many thanks.

David Epstein

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