Class: Class

Inherits:
Object
  • Object
show all
Defined in:
lib/couchrest/support/class.rb

Overview

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

class Person
  cattr_accessor :hair_colors
end

Person.hair_colors = [:brown, :black, :blonde, :red]

Instance Method Summary collapse

Instance Method Details

#cattr_accessor(*syms) ⇒ Object 



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# File 'lib/couchrest/support/class.rb', line 74

def cattr_accessor(*syms)
  cattr_reader(*syms)
  cattr_writer(*syms)
end

#cattr_reader(*syms) ⇒ Object 



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# File 'lib/couchrest/support/class.rb', line 34

def cattr_reader(*syms)
  syms.flatten.each do |sym|
    next if sym.is_a?(Hash)
    class_eval(<<-EOS, __FILE__, __LINE__ + 1)
      unless defined? @@#{sym}  # unless defined? @@hair_colors
        @@#{sym} = nil          #   @@hair_colors = nil
      end                       # end
                                #
      def self.#{sym}           # def self.hair_colors
        @@#{sym}                #   @@hair_colors
      end                       # end
                                #
      def #{sym}                # def hair_colors
        @@#{sym}                #   @@hair_colors
      end                       # end
    EOS
  end
end

#cattr_writer(*syms) ⇒ Object 



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# File 'lib/couchrest/support/class.rb', line 53

def cattr_writer(*syms)
  options = syms.extract_options!
  syms.flatten.each do |sym|
    class_eval(<<-EOS, __FILE__, __LINE__ + 1)
      unless defined? @@#{sym}                       # unless defined? @@hair_colors
        @@#{sym} = nil                               #   @@hair_colors = nil
      end                                            # end
                                                     #
      def self.#{sym}=(obj)                          # def self.hair_colors=(obj)
        @@#{sym} = obj                               #   @@hair_colors = obj
      end                                            # end
                                                     #
      #{"                                            #
      def #{sym}=(obj)                               # def hair_colors=(obj)
        @@#{sym} = obj                               #   @@hair_colors = obj
      end                                            # end
      " unless options[:instance_writer] == false }  # # instance writer above is generated unless options[:instance_writer] == false
    EOS
  end
end

#extlib_inheritable_accessor(*syms, &block) ⇒ Array[#to_s]

Defines class-level inheritable attribute accessor. Attributes are available to subclasses, each subclass has a copy of parent’s attribute.

Parameters:

  • *syms (Array[*#to_s, Hash{:instance_writer => Boolean}]) —

    Array of attributes to define inheritable accessor for.

  • syms (Hash) —

    a customizable set of options

Options Hash (*syms):

  • :instance_writer (Boolean) —

    if true, instance-level inheritable attribute writer is defined.

Returns:

  • (Array[#to_s]) —

    An Array of attributes turned into inheritable accessors.



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# File 'lib/couchrest/support/class.rb', line 153

def extlib_inheritable_accessor(*syms, &block)
  extlib_inheritable_reader(*syms)
  extlib_inheritable_writer(*syms, &block)
end

#extlib_inheritable_reader(*ivars) ⇒ Array[#to_s]

TODO:

Do we want to block instance_reader via :instance_reader => false

TODO:

It would be preferable that we do something with a Hash passed in (error out or do the same as other methods above) instead of silently moving on). In particular, this makes the return value of this function less useful.

Defines class-level inheritable attribute reader. Attributes are available to subclasses, each subclass has a copy of parent’s attribute.

Parameters:

  • *syms (Array[#to_s]) —

    Array of attributes to define inheritable reader for.

Returns:

  • (Array[#to_s]) —

    Array of attributes converted into inheritable_readers.



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# File 'lib/couchrest/support/class.rb', line 92

def extlib_inheritable_reader(*ivars)
  instance_reader = ivars.pop[:reader] if ivars.last.is_a?(Hash)

  ivars.each do |ivar|
    self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
      def self.#{ivar}
        return @#{ivar} if self.object_id == #{self.object_id} || defined?(@#{ivar})
        ivar = superclass.#{ivar}
        return nil if ivar.nil? && !#{self}.instance_variable_defined?("@#{ivar}")
        @#{ivar} = ivar && !ivar.is_a?(Module) && !ivar.is_a?(Numeric) && !ivar.is_a?(TrueClass) && !ivar.is_a?(FalseClass) ? ivar.dup : ivar
      end
    RUBY
    unless instance_reader == false
      self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
        def #{ivar}
          self.class.#{ivar}
        end
      RUBY
    end
  end
end

#extlib_inheritable_writer(*ivars) ⇒ Array[#to_s]

TODO:

We need a style for class_eval <<-HEREDOC. I’d like to make it class_eval(<<-RUBY, __FILE__, __LINE__), but we should codify it somewhere.

Defines class-level inheritable attribute writer. Attributes are available to subclasses, each subclass has a copy of parent’s attribute.

Parameters:

  • *syms (Array[*#to_s, Hash{:instance_writer => Boolean}]) —

    Array of attributes to define inheritable writer for.

  • syms (Hash) —

    a customizable set of options

Returns:

  • (Array[#to_s]) —

    An Array of the attributes that were made into inheritable writers.



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# File 'lib/couchrest/support/class.rb', line 126

def extlib_inheritable_writer(*ivars)
  instance_writer = ivars.pop[:writer] if ivars.last.is_a?(Hash)
  ivars.each do |ivar|
    self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
      def self.#{ivar}=(obj)
        @#{ivar} = obj
      end
    RUBY
    unless instance_writer == false
      self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
        def #{ivar}=(obj) self.class.#{ivar} = obj end
      RUBY
    end

    self.send("#{ivar}=", yield) if block_given?
  end
end