code: function countColumn(string, end, tabSize, startIndex, startValue) {
      if (end == null) {
        end = string.search(/[^\s\u00a0]/);
        if (end == -1) end = string.length;
      }
      for (var i = startIndex || 0, n = startValue || 0; i < end; ++i) {
        if (string.charAt(i) == "\t") n += tabSize - (n % tabSize);
        else ++n;
      }
      return n;
    }
docs: Counts the column offset in a string, taking tabs into account. Used mostly to find indentation.