1. win32lib: Scope of event handlers?
I've moved some routines into an include file and find that they now do not
work for reasons that are a mystery to me.
One of the procedures creates a number of PushButtons, storing the handles
in a sequence and setting onClick to another routine in the include file,
using routine_id. It sets up the buttons just fine, but the onClick routines
don't work.
When the same code is in the main file, it seems to work just fine. The
procedures are declared global.
Any idea what the problem could be?
----------------
Dr. John Coonrod, Vice President, jc at thp.org
The Hunger Project, 15 East 26th Street, NY, NY 10010 www.thp.org
2. Re: win32lib: Scope of event handlers?
I perhaps have figured this out.
It appears that setting onClick must not be done inside a procedure. Is that
true?
When I moved all references to onClick outside routines, things were ok.
===== Original Message from Euphoria Programming for MS-DOS
<EUPHORIA at LISTSERV.MUOHIO.EDU> at 8/15/00 7:12 am
>I've moved some routines into an include file and find that they now do not
>work for reasons that are a mystery to me.
>
>One of the procedures creates a number of PushButtons, storing the handles
>in a sequence and setting onClick to another routine in the include file,
>using routine_id. It sets up the buttons just fine, but the onClick routines
>don't work.
>
>When the same code is in the main file, it seems to work just fine. The
>procedures are declared global.
>
>Any idea what the problem could be?
>
3. Re: win32lib: Scope of event handlers?
John Coonrod wrote:
> It appears that setting onClick must not be
> done inside a procedure. Is that true?
No, you can set the code anywhere. It's just simple variable assignment.
More likely, the scope of routine_id is causing you grief. Remember that
routine_id can only be called *after* the routine is defined. You probably
did something like this:
onClick[me] = routine_id("foo")
procedure foo( ... )
and onClick[me] was set to -1. By moving the assignment, you probably moved
routine_id after the routine:
procedure_foo( ... )
onClick[me] = routine_id("foo")
and things started working again. Perhaps I should have written wrappers
like this:
procedure OnClick( integer id, integer callback )
if callback = -1 then
abortErr("OnClick: Routine not defined")
else
onClick[id] = routine
end if
end procedure
This would save people from a lot of grief by giving a warning, although
writing:
OnClick( me, routine_id("foo") )
is still a bit awkward. I *really* wish I could write:
procedure OnClick( integer id, sequence routine )
callback = routine_id(routine)
if callback = -1 then
abortErr("OnClick: Routine " & routine & " not defined")
else
onClick[id] = routine
end if
end procedure
and then you coule write:
OnClick( me, "foo" )
but I can't, because of the scoping issues with routine_id. Namely, if you
use this routine, you can only pass it routines that have been defined
*before* this routine was defined. *grumble*
-- David Cuny
