Class: Class

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

Overview

Allows attributes to be shared within an inheritance hierarchy, but where each descendant gets a copy of their parents’ attributes, instead of just a pointer to the same. This means that the child can add elements to, for example, an array without those additions being shared with either their parent, siblings, or children, which is unlike the regular class-level attributes that are shared across the entire hierarchy.

Instance Method Summary collapse

Instance Method Details

#cattr_accessor(*syms) ⇒ Array[#to_s]

Defines class-level (and optionally instance-level) attribute accessor.

Parameters:

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

    Array of attributes to define accessor for.

  • syms (Hash) —

    a customizable set of options

Options Hash (*syms):

  • :instance_writer (Boolean) —

    if true, instance-level attribute writer is defined.

Returns:

  • (Array[#to_s]) —

    List of attributes that were made into accessors



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# File 'lib/couchrest/support/class.rb', line 94

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

#cattr_reader(*syms) ⇒ Array[#to_s]

TODO:

Is this inconsistent in that it does not allow you to prevent

Defines class-level and instance-level attribute reader.

an instance_reader via :instance_reader => false

Parameters:

  • *syms (Array) —

    Array of attributes to define reader for.

Returns:

  • (Array[#to_s]) —

    List of attributes that were made into cattr_readers



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# File 'lib/couchrest/support/class.rb', line 38

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

#cattr_writer(*syms) ⇒ Array[#to_s]

Defines class-level (and optionally instance-level) attribute writer.

Parameters:

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

    of attributes to define writer for.

  • syms (Hash) —

    a customizable set of options

Options Hash (*syms):

  • :instance_writer (Boolean) —

    if true, instance-level attribute writer is defined.

Returns:

  • (Array[#to_s]) —

    List of attributes that were made into cattr_writers



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# File 'lib/couchrest/support/class.rb', line 64

def cattr_writer(*syms)
  options = syms.last.is_a?(Hash) ? syms.pop : {}
  syms.flatten.each do |sym|
    class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
unless defined? @@#{sym}
@@#{sym} = nil
end
 
def self.#{sym}=(obj)
@@#{sym} = obj
end
RUBY
 
    unless options[:instance_writer] == false
      class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
def #{sym}=(obj)
@@#{sym} = obj
end
RUBY
    end
  end
end

#class_inheritable_accessor(*syms) ⇒ Array[#to_s]

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

define inheritable accessor for.

Parameters:

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

    Array of attributes to

  • 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 171

def class_inheritable_accessor(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_writer(*syms)
end

#class_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

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

(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.

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 112

def class_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.is_a?(Symbol) ? 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

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

TODO:

We need a style for class_eval <<-HEREDOC. I’d like to make it

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

define inheritable writer for. class_eval(<<-RUBY, __FILE__, __LINE__), but we should codify it somewhere.

Parameters:

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

    Array of attributes to

  • 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 146

def class_inheritable_writer(*ivars)
  instance_writer = ivars.pop[:instance_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
  end
end