Module: Attic

Defined in:
lib/attic.rb,
lib/attic/class_methods.rb,
lib/attic/instance_methods.rb

Overview

Attic::InstanceMethods

Defined Under Namespace

Modules: ClassMethods, InstanceMethods

Constant Summary collapse

VERSION = 
"1.0.1".freeze

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.construct(obj) ⇒ Object

A convenince method at the class level for including ConstructMethods in the given object specifically.

e.g.

  Add Attic support to all objects available now and
  in the future:

    Attic.construct(Object)

  which is equivalent to:

    class Object; include Attic::ClassMethods; end



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# File 'lib/attic.rb', line 119

def self.construct(obj)
  obj.include Attic::ClassMethods
end

.extended(obj) ⇒ Object 



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# File 'lib/attic.rb', line 129

def self.extended(obj)
  # If the class has already been extended, we don't need
  # to add the class methods again.
  return if obj.ancestors.member? self

  # Add the instance methods for accessing attic variables
  obj.send :include, Attic::InstanceMethods

  # If the object doesn't have a dedicated singleton class
  # an exception will be raised so it can be caught and
  # handled appropriately.
  obj.attic.instance_variable_defined?("@attic_variables")

  obj.attic.instance_variable_set("@attic_variables", [])

  def obj.inherited(klass)
    super
    attic_vars = self.attic_variables.clone
    klass.attic.instance_variable_set("@attic_variables", attic_vars)
  end
  if obj.method_defined? :instance_variables
    instance_variables_orig = obj.instance_method(:instance_variables)
    obj.define_method :instance_variables do
      ret = instance_variables_orig.bind(self).call.clone
      ret.reject! { |v| v.to_s =~ /^@___?attic/ }  # match 2 or 3 underscores
      ret
    end
    obj.define_method :all_instance_variables do
      instance_variables_orig.bind(self).call
    end
  end

rescue TypeError => e
  raise NoSingletonError, obj, caller
end

.included(obj) ⇒ Object

Friendly exception to say we’re not to be included

Raises:

  • (RuntimeError) 


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# File 'lib/attic.rb', line 125

def self.included(obj)
  raise RuntimeError, "Did you mean to `extend Attic`` in #{obj}"
end

Instance Method Details

#attic(*names) ⇒ Object

A class method for defining variables to store in the attic.

  • names is a list of variables names. Accessor methods are created for each variable name in the list.

Returns an Array of all attic variables for the current class unless no arguments are given in which case it returns its singleton.

e.g.

String.extend Attic
String.attic :timestamp

In this example, attic created two instance methods:

  • String#timestamp for getting the value

  • String#timestamp for setting the value



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# File 'lib/attic.rb', line 182

def attic(*names)
  return singleton_class if names.empty?

  names.each do |name|
    next if attic_variable? name

    self.attic_variables << name

    unless method_defined?(name)
      define_method(name) do
        attic_variable_get name
      end
    end

    unless method_defined?("#{name}=")
      define_method("#{name}=") do |val|
        attic_variable_set name, val
      end
    end
  end

  attic_variables  # only after defining new attic vars
end

#attic? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/attic.rb', line 206

def attic?
  return false if NoSingletonError.member? self

  singleton_class?

rescue TypeError
  NoSingletonError.add_member self
  false
end

#attic_variable?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/attic.rb', line 229

def attic_variable?(name)
  attic_variables.member? name
end

#attic_variables ⇒ Object

Returns an Array of attic variables for the current class. e.g.

String.extend Attic
String.attic :timestamp
String.attic_variables     # => [:timestamp]



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# File 'lib/attic.rb', line 223

def attic_variables
  a = attic.instance_variable_get("@attic_variables")
  a ||= attic.instance_variable_set("@attic_variables", [])
  a
end