>>> I always had the (wrong!) impression that every openStack handler is
>>> only called once, and also that it belongs to the stack containing it.
Others have described the hierarchy, but I thought I'd offer some clarification
related to why some people have suggested to put the openStack trap of your
main stack in the first card of the stack instead of the stack script, and to
offer an alternative:
If you put an openStack handler in the stack script of your mainstack, and just
open the mainstack, the "openStack" message passes through the hierarchy like
this:
openStack
-> script of first card of mainstack
-> stack script of mainstack
-> backscripts/libraries/etc.
If you open a *substack* of the mainstack, the openStack message passes through
the hierarchy like this:
openStack
-> script of first card of substack
-> stack script of substack
-> stack script of mainstack
-> backscripts/libraries/etc.
Notice that the message does NOT go to the first card of the mainstack! So if
you move your openStack handler of your mainstack from the stack script to the
first card of the mainstack, it will still be triggered when the *mainstack*
opens, but it will NOT be triggered when a *substack* opens.
Coming from HyperCard/SuperCard development, and in my early years of working
with MetaCard/Revolution, it seemed "weird" to me that I would have
stack-related handlers in a card script. So to keep the handler in the
mainstack script but *not* have it trigger when a substack opened, I had my
mainstack's openStack handler look like this:
on openStack
if the owner of the target is me then
-- do mainstack-only stuff
else
-- either do nothing, or do substack-only stuff
end if
end openStack
Since the openStack message hits the card first, the "owner of the target" is
the mainstack (or substack) itself… so by testing "if the owner of the target
is me" inside the mainstack's stack script, I could isolate openStack messages
from the mainstack opening vs. any of its substacks.
Hope this helps clarify things,
Ken Ray
Sons of Thunder Software, Inc.
Email: k...@sonsothunder.com
Web Site: http://www.sonsothunder.com/
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