Class: Module

Inherits:
Object show all
Defined in:
lib/ruby/module.rb

Instance Method Summary collapse

Instance Method Details

#abstract(name, *params) ⇒ void

This method returns an undefined value.

Creates an abstract method

Examples:

class Collection
  abstract :size
  abstract :add, :args => %w(item)
end


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# File 'lib/ruby/module.rb', line 12

def abstract(name, *params)
  if params.last.is_a?(Hash)
    # abstract :method, :args => %w(a b c)
    params = params.last[:args]
  end

  file, line, = Stupidedi.caller

  if params.empty?
    class_eval(<<-RUBY, file, line.to_i - 1)
      def #{name}(*args)
        raise NoMethodError,
          "method \#{self.class.name}.#{name} is abstract"
      end
    RUBY
  else
    class_eval(<<-RUBY, file, line.to_i - 1)
      def #{name}(*args)
        raise NoMethodError,
          "method \#{self.class.name}.#{name}(#{params.join(', ')}) is abstract"
      end
    RUBY
  end
end

#delegate(*params) ⇒ void

This method returns an undefined value.

Creates a method (or methods) that delegates messages to an instance variable or another instance method.

Examples:

class WrappedCollection
  delegate :size, :add, :to => :@wrapped

  def initialize(wrapped)
    @wrapped = wrapped
  end
end


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# File 'lib/ruby/module.rb', line 50

def delegate(*params)
  unless params.last.is_a?(Hash)
    raise ArgumentError,
      "last argument must be :to => ..."
  end

  methods = params.init
  target  = params.last.fetch(:to) or
    raise ArgumentError,
      ":to => ... cannot be nil"

  file, line, = Stupidedi.caller

  for m in methods
    if m.to_s =~ /=$/
      class_eval(<<-RUBY, file, line.to_i - 1)
        def #{m}(value)
          #{target}.#{m}(value)
        end
      RUBY
    else
      class_eval(<<-RUBY, file, line.to_i - 1)
        def #{m}(*args, &block)
          #{target}.#{m}(*args, &block)
        end
      RUBY
    end
  end
end