Oh well, you are right about that: the difference is too low to be noticable for normal use. I was just picking up merlyn's glove ;-}.

I just added the cmpthese stats when I saw your posting. Take a look at them. Some nitbits: I would call the swab 'insert'. But that can be done by substr as well... benchmarks coming up....

         Rate inssub regmap  regex fixreg substr
inssub 13.7/s     --   -95%   -97%   -97%   -97%
regmap  260/s  1800%     --   -34%   -35%   -47%
regex   395/s  2784%    52%     --    -1%   -20%
fixreg  398/s  2809%    53%     1%     --   -19%
substr  491/s  3483%    89%    24%    23%     --
[download]

That insert must be *really* inefficient :-)

Jeroen
"We are not alone"(FZ)

Let me add the new code:

use Benchmark;
 
undef $/;
open DATA, "/home/jeroen/texs/review/reviewnew.tex" or die $!;
$str = <DATA>;
open DUMP, ">/dev/null";
 
$result = timethese( -5, {
 'regex' =>
  sub {
   $a = $str;
   $b = '';
   $b .= "$1\n" while $a=~/\G(.{1,80})/gs;
   print DUMP "$b";
  },
 'regmap' =>
  sub {
   $a = $str;
   $b = '';
   print DUMP map "$_\n", $a=~/\G(.{1,80})/gs;
  },
'fixreg'=>
  sub {
   $a = $str;
   $b = '';
   $b .= "$1\n" while $a=~/\G(.{1,80})/gos;
   print DUMP "$b";
  },
 'substr' =>
  sub {
    $a = $str;
    $b='';
    $b .= substr( $a, 0, 80, '')."\n" while length($a) >80;
    print DUMP "$b$a";
  },
 'inssub' =>
  sub {
    $a = $str;
    $idx = 0;
    substr( $a, $idx+=81, 0)="\n" while $idx< (length( $a) - 80 );
    print DUMP "$a";
  }
 }, 'none');
 
Benchmark::cmpthese($result);
[download]