[Gambas-user] Finally/Catch and Return: How is that meant to be used?

[Martin Fischer]

Hi all,

I think I don't understand the approach to error handling gambas has chosen.

Let's take a simple, very common problem: a function that shall return
the id (int) of something. To get this id, a looooong and very
complicated sequence of steps have to be taken. This involves the
allocation of resources that have to be cleaned up in any case. All
kinds of errors could happen on the way (errors might get risen).

Here is pseudocode for this:

-----------------------
Public Function getComplicatedId() As Integer
	Dim result As Integer

	' do some very complicated stuff
	' resources are allocated on the way. E.g. heap Alloc

	Return result

Finally
	' clean up resources here
Catch
	' do some logging here
	Error.Raise("Can't handle this!")
End
-----------------------

The first problem with this code is that the "Return result" causes the
Finally block to be skipped.

Moving the "Return result" as last statement into the Finally block does
work but prevents the Catch block to be executed in case of an error. Bad.

I'm sure that there is a way to handle cleanup and errors in a clean
manner (I mean: without Gotos and Labels). I just can't see how to do it
with Return, Finally and Catch...

Does anyone have an explanation or example or reference to a
sample/documentation for this problem?

Thanks

__________________________________
Martin Fischer