I think that will also mess up anything which is doing an eval and then checking $@ afterwards.

use Carp qw(confess cluck);
BEGIN {
    *CORE::GLOBAL::warn = \&cluck;
    *CORE::GLOBAL::die = \&confess;
}

sub foo { bar() }
sub bar { print "in bar\n"; die "badness!" }

eval { foo };
print "ack - $@" if $@;

__output__

in bar
ack - badness! at - line 8
        main::bar() called at - line 7
        main::foo() called at - line 10
        eval {...} called at - line 10
[download]

use Carp qw(confess cluck);
BEGIN {
    *CORE::GLOBAL::warn = \&cluck;
    *CORE::GLOBAL::die = \&confess;
}

sub foo { bar() }
sub bar { print "in bar\n";die( bless{akey=>"a string"} ) }

use DDS;
eval { foo };
print "ack: ", Dump($@) if ref $@; 

__output__

in bar
ack: $main1 = bless( { akey => 'a string' }, 'main' );
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The first example is probably OK as long as your check against $@ is both strict enough and liberal enough to not be confused by the stack trace. The second example has a bigger problem, eval {foo} works but foo() on it's own doesn't give a stack trace.

The solution is not a one-liner, it needs to pay attention to $^S which indicates whether we're being eval()ed or not. It should also play well with other die/warn handlers. diagnostics does this. I'll submitting a small patch to add stack traces to warns and to allow a mode that turns off the verbose explanations, then I'll be happy.

The second example has a bigger problem, eval {foo} works but foo() on it's own doesn't give a stack trace.

It doesn't?

use Carp qw(confess cluck);
BEGIN {
    *CORE::GLOBAL::warn = \&cluck;
    *CORE::GLOBAL::die = \&confess;
}

sub foo { bar() }
sub bar { print "in bar\n"; die "badness!" }

foo();

__output__

in bar
badness! at - line 8
        main::bar() called at - line 7
        main::foo() called at - line 10
[download]

The solution is not a one-liner, it needs to pay attention to $^S which indicates whether we're being eval()ed or not.

But this is dealt with by perl, so even with die and warn overridden the value of $^S will be unaffected.

It should also play well with other die/warn handlers.

And it does

use Carp qw(confess cluck);
BEGIN {
    *CORE::GLOBAL::warn = \&cluck;
    *CORE::GLOBAL::die = \&confess;
}

$SIG{__DIE__}  = sub { print "I died: @_\n" };
$SIG{__WARN__} = sub { print "watch out: @_\n" };

sub foo { bar() }
sub bar { print "in &bar\n"; warn "it's behind you!" }

sub baz { qux() }
sub qux { print "in &qux\n"; die "ack!" }

eval { foo; baz; };

print "The End.\n";

__output__

in &bar
watch out: it's behind you! at - line 12
        main::bar() called at - line 11
        main::foo() called at - line 17
        eval {...} called at - line 17

in &qux
I died: ack! at - line 15
        main::qux() called at - line 14
        main::baz() called at - line 17
        eval {...} called at - line 17

The End.
[download]

My point is, is that overriding die and warn with the corresponding calls from Carp should work fine as they inevitably call die and warn anyhow. The only problems you should run into with these overrides is in existing code where exception handling could very well get muddled, but this shouldn't be a problem if you use subs to localise this behaviour to a given package e.g

{
  package Expressive;

  use Carp qw(confess cluck);

  use subs qw( die warn );

  *die  = \&confess;
  *warn = \&cluck;

  sub test {
    warn "warning in ".__PACKAGE__."::test\n";
    die  "dieing in ".__PACKAGE__."::test\n";
  }
}

print "using Expressive::\n";
eval { Expressive::test };
print $@;

print "\nusing main::\n";
eval {
  warn "warning in ".__PACKAGE__;
  die  "dieing in ".__PACKAGE__;
};
print $@;

print "\ndone.\n";

__output__

using Expressive::
warning in Expressive::test
        Expressive::test() called at pmsopw_379099.pl line 18
        eval {...} called at pmsopw_379099.pl line 18
dieing in Expressive::test
        Expressive::test() called at pmsopw_379099.pl line 18
        eval {...} called at pmsopw_379099.pl line 18

using main::
warning in main at pmsopw_379099.pl line 23.
dieing in main at pmsopw_379099.pl line 24.

done.
[download]

HTH

_________
broquaint