live
	   Returns the result of the given expression if no
	   exception is thrown.

	   If an exception is thrown an object is returned that
	   evaluates to false when used in any standard boolean
	   test or comparison operation ("<", "<=", ">", ">=",
	   "==", "!=", "lt", "le", "gt", "ge", "eq" and "ne").

	   This can be used to simplify testing for exceptions.
	   For example:

		   foreach my $n (3,2,1,0) {
			   is live{$n/$n}, 1, "$n/$n == 1";
		   };

	   will produce

		   ok 1 - 3/3 == 1
		   ok 2 - 2/2 == 1
		   ok 3 - 1/1 == 1
		   not ok 4 - 0/0 == 1
		   # Failed test (test.pl at line 37)
		   #   got: 'DIED: Illegal division by zero at test.pl line 37.'
		   # expected: '1'

	   NOTE: that it is an object not a false value that is
	   returned when an exception occurred.

		   # this will pass even if foo dies
		   ok(refaddr live {$o->foo}, 'foo returns object';

		   # this will pass even if foo dies
		   unlike live {$o->foo}, '/fribble/', 'no fribble';

	   Appropriate care must be taken.