| alias_method | -> | alias_setter |
Alias an accessor. This create an alias for both a reader and a writer.
class AttrSetterExample
attr_setter :a
alias_setter :b, :a
end
x = AttrSetterExample.new
x.b(1)
x.a #=> 1
CREDIT: Trans |
||
| target | -> | name |
| extend | -> | can |
An alias for extend.
module EgCan
def foo; "foo"; end
end
class EgCanClass
can EgCan
end
EgCanClass.foo #=> 'foo'
BTW, why is Forwardable an -able? It‘s not a mixin! |
||
| === | -> | class? |
Alias for #===. This provides a verbal method for inquery.
s = "HELLO" String.class?(s) #=> true |
||
| undef_method | -> | nodef |
| Alias for undef_method. This has been called "nodef" instead of undef to help clarify that it doesn‘t get rid of the method, but rather represses repsonse. | ||
| remove_method | -> | remove |
| Alias for remove_method. This method actually "undefines" a method and will raise an error is the method is not defined in receiver. | ||
Rename methods.
module AStar
def a; "a"; end
end
BStar = AStar * { :a => :b }
class XStar; include BStar; end
XStar.new.b #=> "a"
CREDIT: Thomas Sawyer, Robert Dober
Combine modules.
module APlus
def a; "a"; end
end
module BPlus
def b; "b"; end
end
CPlus = APlus + BPlus
class XPlus; include CPlus; end
XPlus.new.a #=> "a"
XPlus.new.b #=> "b"
Note that in the old version of traits.rb we cloned modules and altered their copies…
def +(other)
mod1 = other.clone
mod2 = clone
mod1.module_eval{ include mod2 }
end
Later it was realized that this thwarted the main benefit that Ruby‘s concept of modules has over traditional traits, inheritance.
CREDIT: Thomas Sawyer, Robert Dober
Subtract modules.
module AMinus
def a; "a"; end
def b; "b"; end
end
CMinus = AMinus - [:a]
class XMinus; include CMinus; end
expect NameError do
XMinus.new.a #=> "a"
end
XMinus.new.b #=> "b"
TODO: Should this use all instance methods, not just public?
CREDIT: Thomas Sawyer, Robert Dober
This function provided a "shortcut" for creating the identity method based on given accessors and returns the Equitable module for inclusion.
include Equitable(:a, :b)
is equivalent to including a module containing:
def ==(other)
self.a == other.a && self.b == other.b
end
def eql?(other)
self.a.eql?(other.a) && self.b.eql?(other.b)
end
def hash()
self.a.hash ^ self.b.hash
end
Encapsulates the common pattern of …
alias_method :foo_without_feature, :foo alias_method :foo, :foo_with_feature
With this, you simply do …
alias_method_chain :foo, :feature
For example
class AliasMethodChainExample
def foo
"foo"
end
def foo_with_feature
"foo!"
end
alias_method_chain :foo, :feature
end
And both aliases are set up for you.
example = AliasMethodChainExample.new example.foo #=> "foo!" example.foo_without_feature #=> "foo"
Query and bang methods (foo?, foo!) keep the same punctuation …
alias_method_chain :foo?, :feature
is equivalent to …
alias_method :foo_without_feature?, :foo? alias_method :foo?, :foo_with_feature?
so you can safely chain foo, foo?, and foo! with the same feature.
CREDIT: Bitsweat, Rails Team
List all instance methods, equivalent to
public_instance_methods + protected_instance_methods + private_instance_methods
TODO: Better name for all_instance_methods?
CREDIT: Trans
Is a given class or module an ancestor of this class or module?
class X ; end class Y < X ; end X.ancestor?(Y)
A module may or may not have a name.
module M; end M.name # => "M"
m = Module.new m.name # => ""
A module gets a name when it is first assigned to a constant. Either via the module or class keyword or by an explicit assignment:
m = Module.new # creates an anonymous module M = m # => m gets a name here as a side-effect m.name # => "M"
Create an attribute method for both getting and setting an instance variable:
attr_setter :a
is equivalent to:
def a(*args)
if args.size > 0
@a = args[0]
self
else
@a
end
end
CREDIT: Trans
Create an tester attribute. This creates a single method used to test the attribute for truth.
attr_tester :a
is equivalent to
def a?
@a ? true : @a
end
Note that this method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Trans
@todo This method will probably be deprecated.
@uncommon
require 'facets/module/attr_tester'
Creates a class-variable attribute that can be accessed both on an instance and class level.
class CARExample
@@a = 10
cattr :a
end
CARExample.a #=> 10
CARExample.new.a #=> 10
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/cattr'
Creates a class-variable attr_accessor that can be accessed both on an instance and class level.
class CAAExample
cattr_accessor :a
end
CAAExample.a = 10
CAAExample.a #=> 10
mc = CAAExample.new
mc.a #=> 10
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/cattr'
Creates a class-variable attr_reader that can be accessed both on an instance and class level.
class CARExample
@@a = 10
cattr_reader :a
end
CARExample.a #=> 10
CARExample.new.a #=> 10
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/cattr'
Creates a class-variable attr_writer that can be accessed both on an instance and class level.
class CAWExample
cattr_writer :a
def self.a
@@a
end
end
CAWExample.a = 10
CAWExample.a #=> 10
CAWExample.new.a = 29
CAWExample.a #=> 29
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/cattr'
Normally when including modules, class/module methods are not extended. To achieve this behavior requires some clever Ruby Karate. Instead class_extend provides an easy to use and clean solution. Simply place the extending class methods in a block of the special module method class_extend.
module Mix
def inst_meth
puts 'inst_meth'
end
class_extend do
def class_meth
"Class Method!"
end
end
end
class X
include Mix
end
X.class_meth #=> "Class Method!"
NOTE: This old class_extension version of this method did not extend the containing class automatically —it had to be done by hand. With class_extend, that is no longer the case.
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Daniel Schierbeck, Thomas Sawyer
THANKS: Nobu Nakada, Ulysses
@uncommon
require 'facets/module/class_extend'
Create an dynamic class inheritable attribute.
Inheritor providse a means to store and inherit data via the class heirarchy. An inheritor creates two methods one named after the key that provides a reader. And one named after key! which provides the writer. (Because of the unique nature of inheritor the reader and writer can‘t be the same method.)
The first argument is the inheritor‘s name. The second argument is the archtype object. This object must be duplicable (via dup). The last argument is either the symbolic operator/method or a block that specifies how one hierarchical level "integrates" with the next.
class X
class_inheritor :x, [], :+
end
class Y < X
end
X.x! << :a
X.x #=> [:a]
Y.x #=> [:a]
Y.x! << :b
X.x #=> [:a]
Y.x #=> [:a, :b]
NOTE: Adding an inheritor directly to Module or Class will probably not do what is expected. Thankfully that usecase is likely a YAGNI, but in anycase it is even more likely that it is not possible with this code.
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Thomas Sawyer
@uncommon
require 'facets/module/class_inheritor'
Like class_inheritor but non-dynamic. The value of the inheritor is copied from the ancestor on first read.
c = Class.new do
def self.x; ['x']; end
end
d = Class.new(c) do
copy_inheritor :x
end
d.x #=> ['x']
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Thomas Sawyer
@uncommon
require 'facets/module/copy_inheritor'
Returns the module which contains this one according to its name.
module ::EncExample
module M
module N
end
end
end
EncExample::M::N.enclosure #=> EncExample::M
The enclosure of top-level and anonymous modules is Object.
EncExample.enclosure #=> Object Module.new.enclosure #=> Object
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
@uncommon
require 'facets/module/enclosure'
Returns all the namespaces of this module according ordered from nearest and moving outwards. The receiver is not contained within the result.
module ::EncExample
module M
module N
end
end
end
EncExample.enclosures #=> [Object]
EncExample::M.enclosures #=> [EncExample, Object]
EncExample::M::N.enclosures #=> [EncExample::M, EncExample, Object]
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
@uncommon
require 'facets/module/enclosures'
Returns the module or class containing the receiver.
module ::HomeExample
module M
module N
end
end
end
HomeExample::M::N.home #=> HomeExample::M
The home of a top-level module/class is Object.
HomeExample.home #=> Object
This method is called home because techinally a module or class is just a constant reference, and as such can reside with multiple namespaces, like any variable. For example:
module OtherPlace
M = ::HomeExample::M
end
In this example, you might think that +OtherPlace::M+’s home would be OtherPlace, but +OtherPlace::M+ is the same object as +HomeExample::M+, and it can have only one "home" —the original location of it‘s definition.
Returns the name of module or class containing the receiver.
module ::HomeExample
module M
module N
end
end
end
HomeExample::M::N.homename #=> "HomeExample::M"
See also Module#basename.
Returns all the namespaces of this module according ordered from nearest and moving outwards. The receiver is not contained within the result.
module ::HouseExample
module M
module N
end
end
end
HouseExample.housing #=> [Object]
HouseExample::M.housing #=> [HouseExample, Object]
HouseExample::M::N.housing #=> [HouseExample::M, HouseExample, Object]
Compare this to +Module.nesting+.
Include a module via a specified space.
module T
def t ; "HERE" ; end
end
class X
include_as :test => T
def t ; test.t ; end
end
X.new.t #=> "HERE"
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
@uncommon
require 'facets/module/method_space'
Converts module methods into instance methods such that the first parameter is passed self. This promotes DRY programming when wishing to offer both inheritable and module callable procedures.
This method is modeled after module_function which essentially has the the opposite effect. Due to implementation limitations, this must use the callback singleton_method_added to emulate module_function when no method names are given.
module MyModule
instance_function
def self.jumble(obj, arg)
obj + arg
end
end
MyModule.jumble("Try", "Me") #=> "TryMe"
s = "Try"
s.extend MyModule
s.jumble("Me") #=> "TryMe"
Note: This used to be a module called PromoteSelf and later Instantize, before becoming a method.
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
@uncommon
require 'facets/module/instance_function'
Access method as a singleton object and retain state.
module ::K
def hello
puts "Hello World!"
end
end
K.instance_method!(:hello).inspect #=> "#<UnboundMethod: K#hello>"
NOTE: This is limited to the scope of the current module/class.
Query whether a public instance method is defined for the module.
CREDIT: Gavin Sinclair, Noah Gibbs
Using integrate is just like using include except the module included is a reconstruction of the one given altered by the commands given in the block.
Convenient commands available are: rename, redef, remove, nodef and wrap. But any module method can be used.
module IntegrateExampleModule
def q ; "q" ; end
def y ; "y" ; end
end
class InegrateExampleClass
integrate IntegrateExampleModule do
undef_method :y
end
end
x = InegrateExampleClass.new
x.q #=> "q"
expect NameError do
x.y
end
This is like revisal, but revisal only returns the reconstructred module. It does not include it.
CREDIT: Trans
Is a given class or module an ancestor of this class or module?
class IsX ; end class IsY < IsX ; end IsY.is?(IsX) #=> true
CREDIT: Trans
Returns the root name of the module/class.
module ::BaseName
class Example
end
end
BaseName::Example.name #=> "BaseName::Example"
BaseName::Example.lastname #=> "Example"
Returns nil when module is anonymous.
CREDIT: Trans
Create a memoized method. This method has been popularized by RSpec.
class LetExample
let(:seed) { rand }
end
eg = LetExample.new
eg.seed == eg.seed
CREDIT: Howard Yeh
@uncommon
require 'facets/module/let'
Creates a class-variable attribute that can be accessed both on an instance and class level.
c = Class.new do
mattr :a
def initialize
@@a = 10
end
end
c.new.a #=> 10
c.a #=> 10
NOTE: The mattr methods may not be as useful for modules as the cattr methods are for classes, becuase class-level methods are not "inherited" across the metaclass for included modules.
NOTE: This methiod is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/mattr'
Creates a class-variable attr_accessor that can be accessed both on an instance and class level.
c = Class.new do
mattr_accessor :a
end
c.a = 10
c.a #=> 10
x = c.new
x.a #=> 10
NOTE: This methiod is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/mattr'
Creates a class-variable attr_reader that can be accessed both on an instance and class level.
c = Class.new do
@@a = 10
mattr_reader :a
end
c.a #=> 10
c.new.a #=> 10
NOTE: This methiod is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/mattr'
Creates a class-variable attr_writer that can be accessed both on an instance and class level.
c = Class.new do
mattr_writer :a
def self.a
@@a
end
end
c.a = 10
c.a #=> 10
c.new.a = 29
c.a #=> 29
NOTE: This methiod is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: David Heinemeier Hansson
@uncommon
require 'facets/module/mattr'
Detect method name clash between modules and/or classes, regardless of method visibility:
module MethodClashExample
module A
def c; end
end
module B
private
def c; end
end
A.method_clash(B) #=> [:c]
end
CREDIT: Thomas Sawyer, Robert Dober
@uncommon
require 'facets/module/method_clash'
Uses method_clash to return true or false if there are method name clashes.
@uncommon
require 'facets/module/method_clash'
Create method namespaces, allowing for method chains but still accessing the object‘s instance.
class A
attr_writer :x
method_space :inside do
def x; @x; end
end
end
a = A.new
a.x = 10
a.inside.x #=> 10
expect NoMethodError do
a.x
end
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Pit Captain
@uncommon
require 'facets/module/method_space'
Translate a module name to a suitable method name.
module ::EgMethodize
module Eg
end
end
EgMethodize.methodize #=> "eg_methodize"
EgMethodize::Eg.methodize #=> "eg_methodize__eg"
Load file directly into module/class namespace.
Please use this with careful consideration. It is best suited to loading plugin-type scripts, and should generally not be used as a substitue for Ruby‘s standard load system.
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Trans
@uncommon
require 'facets/module/module_load'
Require file into module/class namespace.
Unlike load this keeps a per-module cache and will not load the same file into the same module more than once despite repeated attempts.
The cache is kept in a global var called +$module_require+.
Please use this with careful consideration. It is best suited to loading plugin-type scripts, and should generally not be used as a substitue for Ruby‘s standard load system.
NOTE: This method is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT: Trans
@uncommon
require 'facets/module/module_load'
Converts a class name to a unix path.
module ::ExamplePathize
module Example
end
end
ExamplePathize.pathize #=> "example_pathize"
ExamplePathize::Example.pathize #=> "example_pathize/example"
Prepend an aspect module to a module. This only works at the module level.
module ::PreX
def x; "x"; end
end
module ::PreU
def x; '{' + super + '}'; end
end
PreX.preextend(PreU)
PreX.x # => "{x}"
NOTE: This is not a common core extension and is not loaded automatically when using require ‘facets‘.
CREDIT Trans
@uncommon
require 'facets/module/preextend'
Return a new module based on another. This includes the original module into the new revised module.
module ReviseExample
def foo; "foo"; end
end
ReviseExample2 = ReviseExample.revise do
alias_method :bar, :foo
end
object = Object.new
object.extend ReviseExample2
object.bar #=> 'foo'
CREDIT: Trans
Query whether a normal (singleton) method is defined for the module.
CREDIT: Gavin Sinclair, Noah Gibbs
Returns the name of module‘s container module.
module ::SpaceName
class Example
end
end
SpaceName::Example.name #=> "SpaceName::Example"
SpaceName::Example.spacename #=> "SpaceName"
This used to be called dirname.
See also Module#basename.
CREDIT: Trans
Create an instance of Object and extend it with self.
mod = Module.new do
def foo; "foo"; end
end
obj = mod.to_obj
obj.foo #=> "foo"
Creates a new method wrapping the previous of the same name. Reference to the old method is passed into the new definition block as the first parameter.
class WrapExample
def foo
"foo"
end
wrap_method(:foo) do |old_meth, *args|
old_meth.call + '!'
end
end
example = WrapExample.new
example.foo #=> 'foo!'
Keep in mind that this cannot be used to wrap methods that take a block.
CREDIT: Trans