code: function add(buf) {
    var self = this
    var compound = self.compoundRules
    var compoundCodes = self.compoundRuleCodes
    var index = -1
    var length = compound.length
    var rule
    var source
    var character
    var offset
    var count
  
    parse(buf, self, self.data)
  
    // Regenerate compound expressions.
    while (++index < length) {
      rule = compound[index]
      source = ''
  
      offset = -1
      count = rule.length
  
      while (++offset < count) {
        character = rule.charAt(offset)
  
        if (compoundCodes[character].length === 0) {
          source += character
        } else {
          source += '(?:' + compoundCodes[character].join('|') + ')'
        }
      }
  
      compound[index] = new RegExp(source, 'i')
    }
  
    return self
  }
docs: Add a dictionary file.