I find a Perl solution a bit more readable: 
sub runcode {
  my @ret;
  while (@_) {
    my ($x, $c) = (shift, 1);
    $c++, shift while $_[0] eq $x;
    push @ret, "$c*$x";
  }
  return @ret;
}

[download]
If you want to golf this: 
# 78 chars
sub RC {
#123456789_123456789_123456789_123456789_123456789_123456789_123456789
+_12345678
 my@r;while(@_){my($x,$c)=(shift,1);$c++,shift while$_[0]eq$x;push@r,"
+$c*$x"}@r
}

[download]
I'm sure it can be shrunk, but I'm kinda busy right now.

japhy -- Perl and Regex Hacker

In reply to Re: PPGA - Prolog-Perl Golf Association: Run-length encoding by japhy
in thread PPGA - Prolog-Perl Golf Association: Run-length encoding by princepawn

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