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

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

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

exports.mask = function(char1, char2){ // Meant for hiding text (if char1 is valid, mask char2 with null character)
  if (char1 == '') return char2;
  else return '';
}

exports.unmask = function(char1, char2){ // Opposite of .mask: shows char2 only if char1 is valid
  if (char1 == '') return '';
  else return char2;
}

exports.flip = function(func){ // Switches this and other in the combination algorithm
  return (char2, char1) => func(char1, char2);
}