Perl Style: Don't Overdo `?:'

Jan 1, 1998 by Tom Christiansen

• Using ?: for control flow may get you talked about. Better to use an if/else. And seldom if ever nest ?:.

      # BAD
      ($pid = fork) ? waitpid($pid, 0) : exec @ARGS;
  
      # GOOD:
      if ($pid = fork) {
          waitpid($pid, 0);
      } else {
          die "can't fork: $!"    unless defined $pid;
          exec @ARGS;
          die "can't exec @ARGS: $!";
      }
  

• Best as an expression:

      $State = (param() != 0) ? "Review" : "Initial";
  
      printf "%-25s %s\n", $Date{$url}
              ? (scalar localtime $Date{$url})
              : "<NONE SPECIFIED>",
  

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Copyright © 1998, Tom Christiansen All rights reserved.