Class: Module

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

Overview

Extends the module object with class/module and instance accessors for class/module attributes, just like the native attr* accessors for instance attributes.

Instance Method Summary collapse

Instance Method Details

#mattr_accessor(*syms, &blk) ⇒ Object Also known as: cattr_accessor

Defines both class and instance accessors for class attributes.



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# File 'lib/accessor_extender/module.rb', line 43

def mattr_accessor(*syms, &blk)
  mattr_reader(*syms, &blk)
  mattr_writer(*syms, &blk)
end

#mattr_reader(*syms) ⇒ Object Also known as: cattr_reader

Defines a class attribute and creates a class and instance reader methods. The underlying the class variable is set to nil, if it is not previously defined.



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# File 'lib/accessor_extender/module.rb', line 10

def mattr_reader(*syms)
  syms.each do |sym|
    raise NameError.new("invalid attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/
    class_eval(<<-EOS, __FILE__, __LINE__ + 1)
      @@#{sym} = nil unless defined? @@#{sym}
      def self.#{sym}
        @@#{sym}
      end
    EOS

    class_variable_set("@@#{sym}", yield) if block_given?
  end
end

#mattr_writer(*syms) ⇒ Object Also known as: cattr_writer

Defines a class attribute and creates a class and instance writer methods to allow assignment to the attribute.



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# File 'lib/accessor_extender/module.rb', line 27

def mattr_writer(*syms)
  syms.each do |sym|
    raise NameError.new("invalid attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/
    class_eval(<<-EOS, __FILE__, __LINE__ + 1)
      @@#{sym} = nil unless defined? @@#{sym}
      def self.#{sym}=(obj)
        @@#{sym} = obj
      end
    EOS

    send("#{sym}=", yield) if block_given?
  end
end