String.class_eval do
  def dirname
    File.expand_path(File.dirname(self))
  end
  
  def expand_path
    File.expand_path(self)
  end
  
  def to_reader
    self.to_sym
  end
  
  def to_writer
    "#{self}=".to_sym
  end
  
  def to_iv
    "@#{self}"
  end
  
  def to_a
    [self]
  end
  
  def interpolate binding
    binding.must_be.a Binding
    return gsub(/\#\{.+?\}/) do |term|
      identifier = term.slice(2 .. term.size-2)
      binding.eval identifier
    end
  end
  
  def self.secure_token
    original = [Time.now, (1..10).map{ rand.to_s }]
    Digest::SHA1.hexdigest(original.flatten.join('--'))
  end
  
  def underscore
    word = self.dup
    word.gsub!(/::/, '/')
    word.gsub!(/([A-Z]+)([A-Z][a-z])/,'\1_\2')
    word.gsub!(/([a-z\d])([A-Z])/,'\1_\2')
    word.tr!("-", "_")
    word.downcase!
    word
  end
  
  def camelize first_letter_in_uppercase = true
    if first_letter_in_uppercase
      gsub(/\/(.?)/) { "::#{$1.upcase}" }.gsub(/(?:^|_)(.)/) { $1.upcase }
    else
      self[0].chr.downcase + camelize(lower_case_and_underscored_word)[1..-1]
    end
  end
  
  def constantize
    names = self.split('::')
    names.shift if names.empty? || names.first.empty?

    constant = Object
    names.each do |name|
      constant = constant.const_defined?(name) ? constant.const_get(name) : constant.const_missing(name)
    end
    constant
  end
  
  class String
    def substitute(*args)
      gsub(*args){yield Regexp.last_match.captures}
    end

    def substitute!(*args)
      gsub!(*args){yield Regexp.last_match.captures}
    end
  end
  
  alias_method :blank?, :empty?
end