Class Class
In: lib/core/facets/class/cattr.rb
lib/core/facets/class/descendents.rb
lib/core/facets/class/methodize.rb
lib/core/facets/class/pathize.rb
lib/core/facets/class/prepend.rb
lib/core/facets/class/to_proc.rb
lib/more/facets/module/class_extend.rb
lib/more/facets/preinitialize.rb
Parent: Object

Methods

External Aliases

new -> postinitialize_new

Public Instance methods

Creates a class-variable attribute that can be accessed both on an instance and class level.

NOTE This used to be a Module method. But turns out it does not work as expected when included. The class-level method is not carried along. So it is now just a Class method. Accordingly, mattr has been deprecated.

CREDIT: David Heinemeier Hansson

[Source]

# File lib/core/facets/class/cattr.rb, line 12
  def cattr( *syms )
    writers, readers = syms.flatten.partition{ |a| a.to_s =~ /=$/ }
    writers = writers.collect{ |e| e.to_s.chomp('=').to_sym }
    readers.concat( writers ) # writers also get readers
    cattr_writer( *writers )
    cattr_reader( *readers )
    return readers + writers
  end

Creates a class-variable attr_accessor that can be accessed both on an instance and class level.

  class MyClass
    cattr_accessor :a
  end

  MyClass.a = 10
  MyClass.a           #=> 10
  mc = MyClass.new
  mc.a                #=> 10

CREDIT: David Heinemeier Hansson

[Source]

# File lib/core/facets/class/cattr.rb, line 102
  def cattr_accessor(*syms)
    cattr_reader(*syms) + cattr_writer(*syms)
  end

Creates a class-variable attr_reader that can be accessed both on an instance and class level.

  class MyClass
    @@a = 10
    cattr_reader :a
  end

  MyClass.a           #=> 10
  MyClass.new.a       #=> 10

CREDIT: David Heinemeier Hansson

[Source]

# File lib/core/facets/class/cattr.rb, line 33
  def cattr_reader( *syms )
    syms.flatten.each do |sym|
      class_eval("unless defined? @@\#{sym}\n@@\#{sym} = nil\nend\n\ndef self.\#{sym}\n@@\#{sym}\nend\n\ndef \#{sym}\n@@\#{sym}\nend\n", __FILE__, __LINE__)
    end
    return syms
  end

Creates a class-variable attr_writer that can be accessed both on an instance and class level.

  class MyClass
    cattr_writer :a
    def a
      @@a
    end
  end

  MyClass.a = 10
  MyClass.a            #=> 10
  MyClass.new.a = 29
  MyClass.a            #=> 29

CREDIT: David Heinemeier Hansson

[Source]

# File lib/core/facets/class/cattr.rb, line 69
  def cattr_writer(*syms)
    syms.flatten.each do |sym|
      class_eval("unless defined? @@\#{sym}\n@@\#{sym} = nil\nend\n\ndef self.\#{sym}=(obj)\n@@\#{sym} = obj\nend\n\ndef \#{sym}=(obj)\n@@\#{sym}=(obj)\nend\n", __FILE__, __LINE__)
    end
    return syms
  end

For Class, class_extend is the same as class_eval. The alternative is to "undef_method :class_extend", but this seems uneccessarily limited.

[Source]

# File lib/more/facets/module/class_extend.rb, line 118
  def class_extend(&blk)
    class_eval(&blk)
  end

List all descedents of this class.

  class X ; end
  class A < X; end
  class B < X; end
  X.descendents  #=> [A,B]

NOTE: This is a intesive operation. Do not expect it to be super fast.

[Source]

# File lib/core/facets/class/descendents.rb, line 12
  def descendents
    subclass = []
    ObjectSpace.each_object( Class ) do |c|
      if c.ancestors.include?( self ) and self != c
        subclass << c
      end
    end
    return subclass
  end

Translate a class name to a suitable method name.

  My::CoolClass.methodize => "my__cool_class"

[Source]

# File lib/core/facets/class/methodize.rb, line 9
  def methodize
    name.methodize
  end

[Source]

# File lib/more/facets/preinitialize.rb, line 90
  def new(*args, &blk)
    o = allocate

    #if respond_to?(:default_instance_variables)
    #  default_instance_variables.each{|k,v| o.instance_variable_set( "@#{k.to_s.gsub(/\W$/,'')}",v )}
    #end

    a = ancestors
    until a.empty?
      m = a.pop
      #if m.private_instance_methods.include?('preinitialize') or m.public_instance_methods.include?('preinitialize')
      if m.method_defined?('preinitialize') or m.private_method_defined?('preinitialize')
        im = instance_method('preinitialize')
        im.arity == 0 ? im.bind(o).call : im.bind(o).call(*args, &blk)
      end
    end

    o.__send__(:initialize, *args, &blk) if o.object_class.private_method_defined?(:initialize)

    o
  end

Converts a class name to a unix path.

  My::CoolClass.pathize  #=> "my/cool_class"

[Source]

# File lib/core/facets/class/pathize.rb, line 9
  def pathize
    name.pathize
  end

Prepend an "aspect module" to a class.

  class Firetruck
    def put_out_fire(option)
      "Put out #{option}"
    end
  end

  module FastFiretruck
    def put_out_fire(option)
      super("very #{option}!")
    end
  end

  Firetruck.prepend(FastFiretruck)

  ft = Firetruck.new
  ft.put_out_fire('fast') #=> "Put out very fast!"

Implementation of this method has some limitations, in that it works by overriding new and allocate.

CREDIT: Trans

TODO: Perhaps rename this to preallocate, b/c of the way it works. It is not really a clean prepend, like that of Module#prepend.

[Source]

# File lib/core/facets/class/prepend.rb, line 30
  def prepend( aspect )
    _new      = method(:new)
    _allocate = method(:allocate)
    (class << self; self; end).class_eval do
      define_method(:new) do |*args|
        o = _new.call(*args)
        o.extend aspect
        o
      end
      define_method(:allocate) do |*args|
        o = _allocate.call(*args)
        o.extend aspect
        o
      end
    end
  end

Convert instatiation of a class into a Proc.

  class Person
    def initialize(name)
      @name = name
    end

    def inspect
      @name.to_str
    end
  end

  %w(john bob jane hans).map(&Person) => [john, bob, jane, hans]

CREDIT: Daniel Schierbeck

[Source]

# File lib/core/facets/class/to_proc.rb, line 18
  def to_proc
    proc{|*args| new(*args)}
  end

[Validate]