Re: Re (tilly) 1: overloading the print function (or alternatives)

[Hot Pastrami]

How about overloading it in a more informative way? Perhaps you could overload print() with something like this (untested):

sub print {
  my $string = join '', @_;
  if ($string =~ /^(Content-type:)/) {
    CORE::print $string;
  }
  else {
    CORE::print "Content-type: text/html\n\n";
    die "You used print() rather than returning a string, you naughty 
+person";
  }
}

Something I DON'T know, however... would one need to prototype this overloaded print() to assure that it would work when used without parenthases, or is that taken care of becuase the built-in print() is already prototyped? You'd probably want to be sure beore doing it this way.

Alan "Hot Pastrami" Bellows

[tilly]

Then you would mess up someone who had inserted:

  print STDERR "Called node 'foo'\n";

as a debugging aid. (The messsage should show up in your webserver's logs.) The following (untested) code is much nicer:

package noprint;
use Carp;

sub PRINT {
  my $msg = Carp::longmess("You must return rather than print");
  print "Content-type: text/plain\n\n$msg";
  die $msg;
}

*PRINTF = *PRINT;

sub TIEHANDLE {
  return bless ({}, shift);
}

and elsewhere in the code:

tie(*NOPRINT, 'noprint');
select(NOPRINT);
# time passes while the page is built.
# Before spitting out the final page:
select(STDOUT);

That catches the newbie error. Without the potential for headaches that overriding print causes.