code: function $$core$$toLatinUpperCase (str) {
          var i = str.length;
  
          while (i--) {
              var ch = str.charAt(i);
  
              if (ch >= "a" && ch <= "z")
                  str = str.slice(0, i) + ch.toUpperCase() + str.slice(i+1);
          }
  
          return str;
      }
docs: Convert only a-z to uppercase as per section 6.1 of the spec