in reply to Fun with Prototypes

More fun for you: ;)

Some people want debug functions to disappear without footprint in production.

Like with Smart::Comments but without source filter.

Try to find a way where changing the prototype of a function &dmp will turn the call to a no op.

Your bar /#(\w+)/, @a; is already quite close, but it's still involving a division. :)

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!

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Re^2: Fun with Prototypes
by tobyink (Canon) on Jul 22, 2017 at 11:22 UTC

    Isn't this sufficiently clear?

    use constant DEBUG => 0;
use Data::Dumper;

# ...

warn Dumper($myvar) if DEBUG;

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    Or PerX::Assert.

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[d/l]
      > Isn't this sufficiently clear?

      > ...

      > warn Dumper($myvar) if DEBUG;

      clear but unnecessarily verbose.

      Cheers Rolf
      (addicted to the Perl Programming Language and ☆☆☆☆ :)
      Je suis Charlie!

[reply]
[d/l]
Re^2: Fun with Prototypes
by LanX (Saint) on Jul 20, 2017 at 12:49 UTC
    an example avoiding a sub-call, unfortunately the division in void context is not optimized away.

    use warnings;
use strict;
use B::Deparse;
use Data::Dump;


use constant DEBUG =>1;

BEGIN {
   unless (DEBUG) {
      *dmp = sub() {
         1;
      }
   } else {
      *dmp = sub($;@){
         shift;
         dd \@_;
      }
   }
}



sub test {
   #$_="#";
   my @a=1..3;
   dmp/#/,
     @a;
}

test();

warn "DEBUG = ",DEBUG,"\n";

print B::Deparse->new()->coderef2text(\&test);

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    OUTPUT 

    DEBUG = 0
{
    use warnings;
    use strict;
    my(@a) = 1..3;
    1 / @a;
}

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    Use of uninitialized value $_ in pattern match (m//) at ... line 27.
DEBUG = 1
[1, 2, 3]
{
    use warnings;
    use strict;
    my(@a) = 1..3;
    dmp /#/, @a;
}

    [download]

    and the warning will create runtime overhead, too :/

    update
    But I think a little overhead is acceptable when debugging.

    another edge case are empty arrays causing a division by zero...

    update:

    fixed minor bug

    Cheers Rolf
    (addicted to the Perl Programming Language and ☆☆☆☆ :)
    Je suis Charlie!

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