Handler called in library can only used passed variables?

Question

I have been redoing a 3000-line program to put handlers in an assortment of libraries.
I've been getting a lot of variable undefined errors after calls to the handlers in the library.
Previously, I declared global variables and the handlers, when they were in the same script, had no problem with them.
Global variables do not seem to include handlers in called libraries as part of their scope.
In fact, I can't even Set a new variable in one of these handlers, unless it has first been passed as a parameter in the handler call.
For example, variable var1 in handler HandyHandler
set var1 to 1
results in a variable undefined error unless I call the handler:
HandyHandler(var1)
thus passing the variable from the main script.
This is more than a little awkward.
Is my perception correct:  all variables in a handler must be defined in the calling script and passed as parameters?

Answer 1

Hello
It's hard to make advice without seeing actual codes. The boiled down essential version to demonstrate the problem would suffice. Also it might help to read the examples and explanations in the following threads.
Externalise functions into a library
https://discussions.apple.com/thread/5116224?tstart=0
tell/scoping problem
https://discussions.apple.com/thread/2477010?start=0&tstart=0
Re: re: my parent
https://discussions.apple.com/message/11852193
Regards,
H
Message was edited by: Hiroto (fixed the last link, but it still may not work...)