c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = join q{,}, 1 .. 40_000;
 ;;
 $s =~ s{
   \b (\d+) (?{ $1 }) \K
   (?: , (\d+) \b (??{ ++$^R != $2 || length($1) != length($2) }))+
   }{-$2}xmsg;
 print qq{'$s'};
"
'1-9,10-99,100-999,1000-9999,10000-40000'

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = join q{,}, 1 .. 150_000;
 ;;
 $s =~ s{
   \b (\d+) (?{ $1 }) \K
     (?: , (\d+) \b (??{ ++$^R != $2 || length($1) != length($2) }))+
   }{-$2}xmsg;
 print qq{'$s'};
"
Complex regular subexpression recursion limit (32766) exceeded at -e line 1.
Complex regular subexpression recursion limit (32766) exceeded at -e line 1.
Complex regular subexpression recursion limit (32766) exceeded at -e line 1.
'1-9,10-99,100-999,1000-9999,10000-42767,42768-75535,75536-99999,100000-132767,132768-150000'

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = join q{,}, 1 .. 150_000;
 ;;
 $s =~ s{
   \b (\d+) (?{ $1 }) \K
   (?:
     (?: , (\d+) \b (??{ ++$^R != $2 || length($1) != length($2) })){1,30000}
   )+
   }{-$2}xmsg;
 print qq{'$s'};
"
'1-9,10-99,100-999,1000-9999,10000-99999,100000-150000'

##</code><code>##

c:\@Work\Perl\monks>perl -wMstrict -le
"use 5.010;
 ;;
 print qq{perl version $]};
 ;;
 my $s = join q{,}, 1 .. 1_500_000;
 ;;
 my $end_point = qr{ , (\d++)
   \b (??{ ++$^R != $2 || length($1) != length($2) })
   }xms;
 ;;
 my $start = time;
 use re 'eval';
 $s =~ s{
   \b (\d++) (?{ $1 }) \K
   (?: $end_point{1,32766})+
   }{-$2}xmsg;
 print qq{'$s'};
 printf qq{in %d seconds \n}, time - $start;
"
perl version 5.010001
'1-9,10-99,100-999,1000-9999,10000-99999,100000-999999,1000000-1500000'
in 18 seconds

##</code><code>##

c:\@Work\Perl\monks>perl -wMstrict -le
"use 5.010;
 ;;
 print qq{perl version $]};
 ;;
 my $s = join q{,}, 1 .. 1_500_000;
 ;;
 my $end_point = qr{ , (\d++)
   (?(?{ ++$^R != $2 || length($1) != length($2) }) (*F))
   }xms;
 ;;
 my $start = time;
 use re 'eval';
 $s =~ s{
   \b (\d++) (?{ $1 }) \K
   (?: $end_point{1,32766})+
   }{-$2}xmsg;
 print qq{'$s'};
 printf qq{in %d seconds \n}, time - $start;
"
perl version 5.010001
'1-9,10-99,100-999,1000-9999,10000-99999,100000-999999,1000000-1500000'
in 3 seconds