Re: Re: Re: Re: Re: Re: should this backspace removal code be done better?

[antirice]

Small problem. You may want to clear out the leading \b's after the while statement. Like many others on this thread, you've been bitten by the terminal's evaluation of \b.

#!/usr/bin/perl -l

$s = "\bt\b\bhello";

sub smack {
  $a = $s;
  $a =~ s/^\cH+//;
  1 while ($a =~ s/[^\cH]\cH//g);
  $a;
}

sub othersmack {
  $a = $s;
  1 while ($a =~ s/[^\cH]\cH//g);
  $a =~ s/^\cH+//;
  $a;
}

print smack();
print othermack();

print "smack correct" unless grep {ord==ord"\b"} split//,smack();
print "othersmack correct" unless grep {ord==ord"\b"} split//,othersma
+ck();
__END__
output:
hello
hello
othersmack correct

However, getting rid of the alternation is a good bit quicker. =)

[shenme]

Hell yes!   It's over 4 times faster than even my attempt, with your repair making it correct.   Gratuitous benchmark below:

               Rate     smack    new1      uk  badkcams othersmack
smack         188/s        --    -96%    -97%      -97%       -99%
new1         5088/s     2607%      --     -8%      -23%       -86%
uk           5517/s     2835%      8%      --      -16%       -85%
badkcams     6594/s     3409%     30%     20%        --       -82%
othersmack  37394/s    19797%    635%    578%      467%         --
            
               Rate     smack    new1      uk  badkcams othersmack
smack        42.6/s        --    -23%    -29%      -43%       -93%
new1         54.9/s       29%      --     -8%      -27%       -91%
uk           59.6/s       40%      9%      --      -21%       -90%
badkcams     75.0/s       76%     37%     26%        --       -88%
othersmack    626/s     1372%   1040%    951%      735%         --

(See shenme's scratchpad for oogly program)