Just for fun, take a look at "Falsify" scalar strings. Its a quick hack that overloads certain strings so that they act FALSE in boolean context. For instance, you could have the odd looking construct:

unless ($error_or_result = my_sub()) {  # FALSE in boolean context
  # but still contains text when stringified
  die "Your error was: $error_or_result\n";  
}
print "Your result was $error_or_result\n";
[download]

Not recommended for production code (for one thing maintanence would be a beast) but fun to play with...

-Blake