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
# File lib/core/facets/class/cattr.rb, line 12 def cattr( *syms ) writers, readers = syms.flatten.partition{ |a| a.to_s =~ %r=$/ } 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
# File lib/core/facets/class/cattr.rb, line 100 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
# File lib/core/facets/class/cattr.rb, line 33 def cattr_reader( *syms ) syms.flatten.each do |sym| class_eval(" unless defined? @@#{sym} @@#{sym} = nil end def self.#{sym} @@#{sym} end def #{sym} @@#{sym} end ", __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
# File lib/core/facets/class/cattr.rb, line 68 def cattr_writer(*syms) syms.flatten.each do |sym| class_eval(" unless defined? @@#{sym} @@#{sym} = nil end def self.#{sym}=(obj) @@#{sym} = obj end def #{sym}=(obj) @@#{sym}=(obj) end ", __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.
# File lib/more/facets/class_extend.rb, line 118 def class_extend(*mods, &block) m = Module.new m.__send__(:include, *mods) m.module_eval(&block) extend(m) m 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.
# 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"
# File lib/core/facets/class/methodize.rb, line 9 def methodize name.methodize end
# 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"
# 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.
# 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
# File lib/core/facets/class/to_proc.rb, line 18 def to_proc proc{|*args| new(*args)} end