On Thu, 2 May 2002, Jim Cromie wrote:
>
> with p5, Ive often written
>
> eval {} or carp "$@ blah";
>
> it seems to work, and it reads nicer (to my eye) than
>
> eval {}; if ($@) {}
>
> but I surmise that it works cuz the return-value from the block is non-zero,
> for successful eval, and 0 or undef when block dies, not cuz of magical
> treatment of $@.
The first one works because the return-value from the eval is undef if the
block fails. The second one is because $@ is true if it failed, and false
if it succeeded.
> I gather that ';' is unneeded in p6, and given that $! is the
> 'exception'al topicalizer,
> is this construct no longer reliant on the last value in the eval block ?
I would imagine that you would do it this way:
try {
...
CATCH { }
}
Only inside the CATCH does $! topicalize; I believe $_ becomes aliased to
that. Remember, C<try> is Perl 6's eval{}.
> put another way, does the 'topicalizer' reflect the exit condition of
> the closure ?
It represents the exception that was thrown, and whatsoever might be
contained in that exception.
Or am I wrong?
Luke
