this enables you to create multiple observations based on multiple other observations

You can fill in (or compute) intra range gaps using basic comparisons, some holding variables and a retained variable.

Example:

Presume no ranges overlap and are order low start first.

data have;
  input id x1 x2; datalines;
1 3 7
1 11 14
2 4 9 
2 15 18
3 1 11
4 11 20
5 1 2
5 3 4
5 5 9
5 10 20
;

data want;
  set have;
  by id;

  length type $6;

  * fill in ranges for every integer 1 through 20;

  if first.id then do;
    bot = 1;
    retain bot;
  end;

  if bot < x1 then do;
    hold1 = x1;
    hold2 = x2;
    x1 = bot;
    x2 = hold1 - 1;
    type = 'gap -';
    output;
    x1 = hold1;
    x2 = hold2;
    type = 'have';
    bot = x2 + 1;
    output;
  end;
  else if x1 <= bot <= x2 then do;
    bot = x2 + 1;
    type = 'have';
    output;
  end;

  if last.id and 20 >= bot > x2 then do;
    type = 'gap +';
    x1 = bot;
    x2 = 20;
    output;
  end;

  keep type id x1 x2 bot;
run;