=pod comment
                  1         2         3         4         5         6
Range	 123456789012345678901234567890123456789012345678901234567890
[ 1, 4]  1111
[ 6, 9]       1111
[ 7,15]        111111111
[10,15]           111111
[17,19]                  111
[20,24]                     11111
[26,29]                           1111
[30,33]                               1111
[34,39]                                   111111
[35,45]                                    11111111111
[40,45]                                         111111
[43,47]                                            11111
[53,57]                                                      11111
[58,59]                                                           11

         1111 1111111111 11111111 1111111111111111111111     1111111
Coaleced
ranges   [1-4] [6-15]     [17-24]  [26-47]                    [53-59]

#! initialise a string  of null as long as the string the ranges pertain to.
my $coal = "\0" x 100; #! Only need be 60 in ths example but the excess bytes don't effect the results.

Using substr as an lvalue, assign a string of range[high]-range[low] x '1' over the null bytes if the result string.

#! fill all the ranges with 1's
substr($coal, $_->[0], $_->[1] - $_->[0] + 1) = 1 x ($_->[1] - $_->[0] + 1) for @ranges;
=cut