use warnings;
use strict;
use Carp;
local $SIG{__WARN__}=sub {die("\t@{[(caller(1))[3]]}() generated warni
+ngs!\n")};

my $foo = {
     aa => { O => 'zz',  C => 'yy'  }, #
     bb => { O => 'xx',  C => 'xx'  },
     cc => { O => undef, C => 'ww'  }, #
     dd => { O => 'vv',  C => undef }, #
     ee => { O => undef, C => undef },
     ff => {             C => undef },
     gg => { O => 0,     C => 0     },
     hh => { O => undef, C => 0     }, #
     ii => { O => undef             }, #
     jj => { O => 0,     C => ' '   }, #
     kk => { O => ' ',   C => 0     }, #
     ll => { O => undef, C => ' '   }, #
     mm => { O => ' ',   C => undef }, #
};

sub BUK{local($^W,$a)=(0,pop);grep{!exists$a->{$_}{O}or$a->{$_}{O}ne$a
+->{$_}{C}}keys%$a}
sub snw{no warnings qw(uninitialized);my$h=pop;grep{$h->{$_}{O}ne$h->{
+$_}{C}}keys %$h}
sub sg_{my$h=pop;grep{!(defined($h->{$_}{O}&&$h->{$_}{C})&&$h->{$_}{O}
+eq$h->{$_}{C}||!defined($h->{$_}{O}||$h->{$_}{C}))}%$h}
sub eg_{my$h=pop;grep{!(($h->{$_}{O}||$;)eq($h->{$_}{C}||$;))}%$h}
sub ddf{$a=pop;grep{$b=$$a{$_};defined$$b{O}!=defined$$b{C}||defined$$
+b{O}&&$$b{O}ne$$b{C}}keys%$a}#98
sub dex{$a=pop;grep{$b=$$a{$_};exists$$b{O}!=exists$$b{C}||defined$$b{
+O}!=defined$$b{C}||defined$$b{O}&&$$b{O}ne$$b{C}}keys%$a}#126
sub tad{my($h)=@_;grep{!exists($h->{$_}->{O})||(defined($h->{$_}->{O})
+?(defined($h->{$_}->{C})?($h->{$_}->{O}ne$h->{$_}->{C}):1):defined($h
+->{$_}->{C}))}keys%$h}#162


print "      Required: aa cc dd ff hh ii jj kk ll mm\n";
print "---------------------------------------------\n";
eval { print "   tadman golf: @{[sort {$a cmp $b} tad($foo)]}\n"; };
print $@ if $@;

eval { print "BrowserUK golf: @{[sort {$a cmp $b} BUK($foo)]}\n"; };
print $@ if $@;

eval { print "sauoq No warns: @{[sort {$a cmp $b} snw($foo)]}\n"; };
print $@ if $@;

eval { print "    Sauoq golf: @{[sort {$a cmp $b} sg_($foo)]}\n"; };
print $@ if $@;

eval { print "  Elusion golf: @{[sort {$a cmp $b} eg_($foo)]}\n"; };
print $@ if $@;

eval { print " Demerphq defd: @{[sort {$a cmp $b} ddf($foo)]}\n"; };
print $@ if $@;

eval { print "Demerphq exist: @{[sort {$a cmp $b} dex($foo)]}\n"; };
print $@ if $@;
__END__
      Required: aa cc dd ff hh ii jj kk ll mm
---------------------------------------------
   tadman golf: aa cc dd ff hh jj kk ll mm
    main::BUK() generated warnings!
sauoq No warns: aa cc dd hh jj kk ll mm
    Sauoq golf: aa cc dd hh jj kk ll mm
  Elusion golf: aa cc dd jj kk ll mm
 Demerphq defd: aa cc dd hh jj kk ll mm
Demerphq exist: aa cc dd ff hh ii jj kk ll mm
[download]

;-)

---
demerphq
my friends call me, usually because I'm late....

If you change the specs to the challenge, any thing is possible.

My version does not produce warnings under the terms of the challenge. Note:the localisation and setting of $^W=0.

---

Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!

If you change the specs to the challenge, any thing is possible.

Advice you should take to heart. From the OP:

Since warnings are supposed to be avoided, use strict; use warnings;

My version does not produce warnings under the terms the unmodifies rules of the challenge. Note:the localisation and setting of $^W=0.

The original terms of the challenge call for it to not produce warnings when run under use warnings. Yours does. The local $^W stuff doesnt have the effect you think it does when used under use warnings; It works the way you think it does when run under only "-w" but that isnt the same thing. It also doesnt work the way you think it does when run under both "-w" and use warnings;. From perllexwarn:

If a piece of code is under the control of the warnings pragma, both the $^W variable and the -w flag will be ignored for the scope of the lexical warning.

Also, next time try running the code before you get so insistant it works the way you think it does....

--- demerphq
my friends call me, usually because I'm late....

I didn't test Juerd's entry as I didn't have FreezeThaw installed. It seems like a complicated way of disabling warnings though?

I'm not interested in disabling warnings. I either avoid them, or don't care about them.

I used FreezeThaw to demonstrate easier syntax.

different if ( defined $x and defined $y and $x ne $y )
          or not ( defined $x and defined $y );
[download]

different if cmpStr($x, $y);
[download]

- Yes, I reinvent wheels.
- Spam: Visit eurotraQ.

Firstly, sorry for mis-spelling your name.

I also apologies for misunderstanding your intent. In the context of the thread, I looked at what FreezeThaw did, and couldn't see the difference between what it did in cmpStr($x,$y) and do{no warnings; $x eq $y). However, as I finally got FreezeThaw.pm installed on my system (actually just copied in as the install mechanism gave me inordanant troubles), I realise that it does more as my test script below shows.

#! perl -sw
use strict;
use FreezeThaw qw(cmpStr freeze);

sub asStr {
    return 'undef' if !defined $_[0];
    return "''" if $_[0] eq '';
    return '0' if $_[0] == 0;
    "$_[0]";
}

my @x = (0,1,'',undef);
my @y = (0,1,'',undef);

print '                  {$^W=0; ($x eq $y)', "\t", '!cmpStr($x,$y)', 
+$/;
for my $x (@x) {
    for my $y (@y) {
        printf '%5s -v- %5s :', asStr($x), asStr($y);

        print "\t", do{local $^W=0;($x eq $y) ? 'Same' : 'Diff';};

        print "\t\t",!cmpStr($x,$y) ? 'Same' : 'Diff', $/;
    }
}
[download]

Giving

C:\test>test
                  {$^W=0; ($x eq $y)    !cmpStr($x,$y)
     0 -v-     0 :       Same            Same
     0 -v-     1 :       Diff            Diff
     0 -v-    '' :       Diff            Diff
     0 -v- undef :       Diff            Diff
     1 -v-     0 :       Diff            Diff
     1 -v-     1 :       Same            Same
     1 -v-    '' :       Diff            Diff
     1 -v- undef :       Diff            Diff
    '' -v-     0 :       Diff            Diff
    '' -v-     1 :       Diff            Diff
    '' -v-    '' :       Same            Same
    '' -v- undef :       Same            Diff # Here!
undef -v-     0 :       Diff            Diff
undef -v-     1 :       Diff            Diff
undef -v-    '' :       Same            Diff # Here!
undef -v- undef :       Same            Same

 1:13:29.67 C:\test>
[download]

---

Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!