OpenEuphoria

Re: win32lib: Scope of event handlers?

• Posted by David Cuny <dcuny at LANSET.COM> Aug 15, 2000
• 436 views

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