anchor.diff:            "signedInt${toString bit}" "${toString bit} bit signed integer.";
   
         in rec {
  -        /* an int with a fixed range
  +        /* An int with a fixed range.
           *
           * Example:
           *   (ints.between 0 100).check (-1)
  
positive.code:         signed32 = sign 32 4294967296;
  
        };
  
      str = mkOptionType {
        name = "str";
  
negative.code:         };
  
          betweenDesc = lowest: highest:
            "${toString lowest} and ${toString highest} (both inclusive)";
          between = lowest: highest: assert lowest <= highest;
            addCheck int (x: x >= lowest && x <= highest) // {
              name = "intBetween";
              description = "Integer between ${betweenDesc lowest highest}.";
            };
          ign = lowest: highest: name: docStart:
            between lowest highest // {
              inherit name;
              description = docStart + " Between ${betweenDesc lowest highest}.";
            };
          unsign = bit: range: ign 0 (range - 1)
            "unsignedInt${toString bit}" "${toString bit} bit unsigned integer.";
  