Re: On the case for exception-based error handling.

[Chaim Frenkel]

>>>>> "PS" == Peter Scott <[EMAIL PROTECTED]> writes:

PS>  From the reactions on this thread so far I am wondering whether the 
PS> message I sent out about it when it had a different name got 
PS> through.  Relevant excerpt:

PS> Well, you could certainly have a pragma that makes throw set $! to the 
PS> message and does a return undef.  But that will only return from the 
PS> current subroutine; there could be a bunch of module subroutines between 
PS> that one and the module user.  Asking module programmers to keep straight 
PS> two possible flows of control in error situations, no less, is asking for 
PS> trouble.  If you think it can be made easier, can you show an example?

Actually, why not simply unwind the call stack to the routine that 
has the pragma active.

        sub foo {use exception; &baz()}

        sub baz { throw "a fit" }

        sub bar {
                no exception;
                &foo();
        }

The unwind logic would treat a scope with no exception set _as if_
each call were wrapped in at try block.

PS> ***But it's entirely up to each programmer whether or not they use 
PS> Fatal-checking***  This is the Perl way anyway.

Fatal checking, is for core functions. And optional for module authors.

Then Fatal.pm and exception.pm could possibly be consolidated.

<chaim>
-- 
Chaim Frenkel                                        Nonlinear Knowledge, Inc.
[EMAIL PROTECTED]                                               +1-718-236-0183