code: function _segment (char) {
    var tmp
    char = char || '.'
    return function (k) {
      if (tmp) {
        tmp += char + k
        if (CLOSE.test(k)) {
          k = tmp
          tmp = ''
        } else {
          return
        }
      } else if (OPEN.test(k)) {
        tmp = k
        if (CLOSE.test(k)) {
          tmp = ''
        } else {
          return
        }
      }
      return k.trim().replace(QUOTES, '$2')
    }
  }
docs: segment path or properties string
  @api private
  @param {String} char - separator char
  @return {Function}