// A set of combine utilities for use with Space.comb()
// Note: char1 is this and char2 is other. char1 will go "over" char2

function add(char1, char2){
  if (char1 == '') return char2;
  else return char1;
}

function sub(char1, char2){
  if (char1 == char2) return '';
  else return char1;
}

exports.add = add;
exports.sub = sub;