Ruby/Справочник/Module
Класс Module
[править]Module является коллекцией из методов и констант. Методы в модуле могут быть методами экземпляра или методами модуля. Метод экземпляра появляется как метод в классе, когда модуль подключен директивой include, методы модуля не выполняются. Напротив, методы модуля могут быть вызваны без создания инкапсулирующего объекта, в то время как методы экземпляра не могут. (См. Module#module_function)
В описании ниже, под параметром syml будем понимать символ, который является строкой в кавычках или объектом класса Symbol (таким, как, например, :name).
module Mod
include Math
CONST = 1
def meth
# ...
end
end
Mod.class #=> Module
Mod.constants #=> ["E", "PI", "CONST"]
Mod.instance_methods #=> ["meth"]
Extends the module object with module and instance accessors for class attributes, just like the native attr* accessors for instance attributes.
Also, modules included into Object need to be scanned and have their instance methods removed from blank slate. In theory, modules included into Kernel would have to be removed as well, but a "feature" of Ruby prevents late includes into modules from being exposed in the first place.
Методы класса
Методы объекта
<=>, <=, <, ===, ==, >=, >, alias_method, ancestors, append_features, attr_accessor, attr_reader, attr_writer, attr, autoload?, autoload, class_eval, class_variable_get, class_variable_set, class_variables, const_defined?, const_get, const_missing, const_set, constants, define_method, extend_object, extended, freeze, include?, included_modules, included, include, instance_methods, instance_method, method_added, method_defined?, method_removed, method_undefined, module_eval, module_function, name, private_class_method, private_instance_methods, private_method_defined?, private, protected_instance_methods, protected_method_defined?, protected, public_class_method, public_instance_methods, public_method_defined?, public, remove_class_variable, remove_const, remove_method, to_s, undef_method
Module::constants
[править]Module.constants => array
Returns an array of the names of all constants defined in the system. This list includes the names of all modules and classes.
p Module.constants.sort[1..5]
produces:
["ARGV", "ArgumentError", "Array", "Bignum", "Binding"]
Module::nesting
[править]Module.nesting => array
Returns the list of Modules nested at the point of call.
module M1
module M2
$a = Module.nesting
end
end
$a #=> [M1::M2, M1]
$a[0].name #=> "M1::M2"
Module::new
[править] Module.new => mod
Module.new {|mod| block } => mod
Creates a new anonymous module. If a block is given, it is passed the module object, and the block is evaluated in the context of this module using module_eval.
Fred = Module.new do
def meth1
"hello"
end
def meth2
"bye"
end
end
a = "my string"
a.extend(Fred) #=> "my string"
a.meth1 #=> "hello"
a.meth2 #=> "bye"
Module#<
[править]mod < other => true, false, or nil
Returns true if mod is a subclass of other. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "A<B").
Module#<=
[править]mod <= other => true, false, or nil
Returns true if mod is a subclass of other or is the same as other. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "A<B").
Module#<=>
[править]mod <=> other_mod => -1, 0, +1, or nil
Comparison---Returns -1 if mod includes other_mod, 0 if mod is the same as other_mod, and +1 if mod is included by other_mod or if mod has no relationship with other_mod. Returns nil if other_mod is not a module.
Module#==
[править]obj == other => true or false obj.equal?(other) => true or false obj.eql?(other) => true or false
Equality---At the Object level, == returns true only if obj and other are the same object. Typically, this method is overridden in descendent classes to provide class-specific meaning. Unlike ==, the equal? method should never be overridden by subclasses: it is used to determine object identity (that is, a.equal?(b) iff a is the same object as b). The eql? method returns true if obj and anObject have the same value. Used by Hash to test members for equality. For objects of class Object, eql? is synonymous with ==. Subclasses normally continue this tradition, but there are exceptions. Numeric types, for example, perform type conversion across ==, but not across eql?, so:
1 == 1.0 #=> true
1.eql? 1.0 #=> false
Module#===
[править]mod === obj => true or false
Case Equality---Returns true if anObject is an instance of mod or one of mod's descendents. Of limited use for modules, but can be used in case statements to classify objects by class.
Module#>
[править]mod > other => true, false, or nil
Returns true if mod is an ancestor of other. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "B>A").
Module#>=
[править]mod >= other => true, false, or nil
Returns true if mod is an ancestor of other, or the two modules are the same. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "B>A").
Module#alias_method
[править]alias_method(new_name, old_name) => self
Makes new_name a new copy of the method old_name. This can be used to retain access to methods that are overridden.
module Mod
alias_method :orig_exit, :exit
def exit(code=0)
puts "Exiting with code #{code}"
orig_exit(code)
end
end
include Mod
exit(99)
produces:
Exiting with code 99
Module#ancestors
[править]mod.ancestors -> array
Returns a list of modules included in mod (including mod itself).
module Mod
include Math
include Comparable
end
Mod.ancestors #=> [Mod, Comparable, Math]
Math.ancestors #=> [Math]
Более одного метода удовлетворяет вашему запросу. Вы можете уточнить ваш запрос, выбрав один из следующих методов:
Module#append_features, Module#append_features===Module#attr===
attr(symbol, writable=false) => nil
Defines a named attribute for this module, where the name is symbol.id2name, creating an instance variable (@name) and a corresponding access method to read it. If the optional writable argument is true, also creates a method called name= to set the attribute.
module Mod
attr :size, true
end
is equivalent to:
module Mod
def size
@size
end
def size=(val)
@size = val
end
end
Module#attr_accessor
[править]attr_accessor(symbol, ...) => nil
Equivalent to calling ``attrsymbol, true on each symbol in turn.
module Mod
attr_accessor(:one, :two)
end
Mod.instance_methods.sort #=> ["one", "one=", "two", "two="]
Module#attr_reader
[править]attr_reader(symbol, ...) => nil
Creates instance variables and corresponding methods that return the value of each instance variable. Equivalent to calling ``attr:name on each name in turn.
Module#attr_writer
[править]attr_writer(symbol, ...) => nil
Creates an accessor method to allow assignment to the attribute aSymbol.id2name.
Module#autoload
[править]mod.autoload(name, filename) => nil
Registers filename to be loaded (using Kernel::require) the first time that name (which may be a String or a symbol) is accessed in the namespace of mod.
module A
end
A.autoload(:B, "b")
A::B.doit # autoloads "b"
Module#autoload?
[править]mod.autoload?(name) => String or nil
Returns filename to be loaded if name is registered as autoload in the namespace of mod.
module A
end
A.autoload(:B, "b")
A.autoload?(:B) # => "b"
Module#class_eval
[править] mod.class_eval(string [, filename [, lineno]]) => obj
mod.module_eval {|| block } => obj
Evaluates the string or block in the context of mod. This can be used to add methods to a class. module_eval returns the result of evaluating its argument. The optional filename and lineno parameters set the text for error messages.
class Thing
end
a = %q{def hello() "Hello there!" end}
Thing.module_eval(a)
puts Thing.new.hello()
Thing.module_eval("invalid code", "dummy", 123)
produces:
Hello there!
dummy:123:in `module_eval': undefined local variable
or method `code' for Thing:Class
Module#class_variable_get
[править]mod.class_variable_get(symbol) => obj
Returns the value of the given class variable (or throws a NameError exception). The @@ part of the variable name should be included for regular class variables
class Fred
@@foo = 99
end
def Fred.foo
class_variable_get(:@@foo) #=> 99
end
Module#class_variable_set
[править]obj.class_variable_set(symbol, obj) => obj
Sets the class variable names by symbol to object.
class Fred
@@foo = 99
def foo
@@foo
end
end
def Fred.foo
class_variable_set(:@@foo, 101) #=> 101
end
Fred.foo
Fred.new.foo #=> 101
Module#class_variables
[править]mod.class_variables => array
Returns an array of the names of class variables in mod and the ancestors of mod.
class One
@@var1 = 1
end
class Two < One
@@var2 = 2
end
One.class_variables #=> ["@@var1"]
Two.class_variables #=> ["@@var2", "@@var1"]
Module#const_defined?
[править]mod.const_defined?(sym) => true or false
Returns true if a constant with the given name is defined by mod.
Math.const_defined? "PI" #=> true
Module#const_get
[править]mod.const_get(sym) => obj
Returns the value of the named constant in mod.
Math.const_get(:PI) #=> 3.14159265358979
Более одного метода удовлетворяет вашему запросу. Вы можете уточнить ваш запрос, выбрав один из следующих методов:
Module#const_missing, Module#const_missing===Module#const_set===
mod.const_set(sym, obj) => obj
Sets the named constant to the given object, returning that object. Creates a new constant if no constant with the given name previously existed.
Math.const_set("HIGH_SCHOOL_PI", 22.0/7.0) #=> 3.14285714285714
Math::HIGH_SCHOOL_PI - Math::PI #=> 0.00126448926734968
Module#constants
[править]mod.constants => array
Returns an array of the names of the constants accessible in mod. This includes the names of constants in any included modules (example at start of section).
Module#define_method
[править] define_method(symbol, method) => new_method
define_method(symbol) { block } => proc
Defines an instance method in the receiver. The method parameter can be a Proc or Method object. If a block is specified, it is used as the method body. This block is evaluated using instance_eval, a point that is tricky to demonstrate because define_method is private. (This is why we resort to the send hack in this example.)
class A
def fred
puts "In Fred"
end
def create_method(name, &block)
self.class.send(:define_method, name, &block)
end
define_method(:wilma) { puts "Charge it!" }
end
class B < A
define_method(:barney, instance_method(:fred))
end
a = B.new
a.barney
a.wilma
a.create_method(:betty) { p self }
a.betty
produces:
In Fred
Charge it!
#<B:0x401b39e8>
Module#extend_object
[править]extend_object(obj) => obj
Extends the specified object by adding this module's constants and methods (which are added as singleton methods). This is the callback method used by Object#extend.
module Picky
def Picky.extend_object(o)
if String === o
puts "Can't add Picky to a String"
else
puts "Picky added to #{o.class}"
super
end
end
end
(s = Array.new).extend Picky # Call Object.extend
(s = "quick brown fox").extend Picky
produces:
Picky added to Array
Can't add Picky to a String
Module#extended
[править]extended(p1)
Not documented
Module#freeze
[править]mod.freeze
Prevents further modifications to mod.
Module#include
[править]include(module, ...) => self
Invokes Module.append_features on each parameter in turn.
Module#include?
[править]mod.include?(module) => true or false
Returns true if module is included in mod or one of mod's ancestors.
module A
end
class B
include A
end
class C < B
end
B.include?(A) #=> true
C.include?(A) #=> true
A.include?(A) #=> false
Module#included
[править]included( othermod )
Callback invoked whenever the receiver is included in another module or class. This should be used in preference to Module.append_features if your code wants to perform some action when a module is included in another.
module A
def A.included(mod)
puts "#{self} included in #{mod}"
end
end
module Enumerable
include A
end
Module#included_modules
[править]mod.included_modules -> array
Returns the list of modules included in mod.
module Mixin
end
module Outer
include Mixin
end
Mixin.included_modules #=> []
Outer.included_modules #=> [Mixin]
Module#instance_method
[править]mod.instance_method(symbol) => unbound_method
Returns an UnboundMethod representing the given instance method in mod.
class Interpreter
def do_a() print "there, "; end
def do_d() print "Hello "; end
def do_e() print "!\n"; end
def do_v() print "Dave"; end
Dispatcher = {
?a => instance_method(:do_a),
?d => instance_method(:do_d),
?e => instance_method(:do_e),
?v => instance_method(:do_v)
}
def interpret(string)
string.each_char {|b| Dispatcher[b].bind(self).call }
end
end
interpreter = Interpreter.new
interpreter.interpret('dave')
produces:
Hello there, Dave!
Module#instance_methods
[править]mod.instance_methods(include_super=true) => array
Returns an array containing the names of public instance methods in the receiver. For a module, these are the public methods; for a class, they are the instance (not singleton) methods. With no argument, or with an argument that is false, the instance methods in mod are returned, otherwise the methods in mod and mod's superclasses are returned.
module A
def method1() end
end
class B
def method2() end
end
class C < B
def method3() end
end
A.instance_methods #=> ["method1"]
B.instance_methods(false) #=> ["method2"]
C.instance_methods(false) #=> ["method3"]
C.instance_methods(true).length #=> 43
Module#method_added
[править]method_added(p1)
Not documented
Module#method_defined?
[править]mod.method_defined?(symbol) => true or false
Returns true if the named method is defined by mod (or its included modules and, if mod is a class, its ancestors). Public and protected methods are matched.
module A
def method1() end
end
class B
def method2() end
end
class C < B
include A
def method3() end
end
A.method_defined? :method1 #=> true
C.method_defined? "method1" #=> true
C.method_defined? "method2" #=> true
C.method_defined? "method3" #=> true
C.method_defined? "method4" #=> false
Module#method_removed
[править]method_removed(p1)
Not documented
Module#method_undefined
[править]method_undefined(p1)
Not documented
Module#module_eval
[править] mod.class_eval(string [, filename [, lineno]]) => obj
mod.module_eval {|| block } => obj
Evaluates the string or block in the context of mod. This can be used to add methods to a class. module_eval returns the result of evaluating its argument. The optional filename and lineno parameters set the text for error messages.
class Thing
end
a = %q{def hello() "Hello there!" end}
Thing.module_eval(a)
puts Thing.new.hello()
Thing.module_eval("invalid code", "dummy", 123)
produces:
Hello there!
dummy:123:in `module_eval': undefined local variable
or method `code' for Thing:Class
Module#module_function
[править]module_function(symbol, ...) => self
Creates module functions for the named methods. These functions may be called with the module as a receiver, and also become available as instance methods to classes that mix in the module. Module functions are copies of the original, and so may be changed independently. The instance-method versions are made private. If used with no arguments, subsequently defined methods become module functions.
module Mod
def one
"This is one"
end
module_function :one
end
class Cls
include Mod
def callOne
one
end
end
Mod.one #=> "This is one"
c = Cls.new
c.callOne #=> "This is one"
module Mod
def one
"This is the new one"
end
end
Mod.one #=> "This is one"
c.callOne #=> "This is the new one"
Module#name
[править]mod.name => string
Returns the name of the module mod.
Module#private
[править]private => self private(symbol, ...) => self
With no arguments, sets the default visibility for subsequently defined methods to private. With arguments, sets the named methods to have private visibility.
module Mod
def a() end
def b() end
private
def c() end
private :a
end
Mod.private_instance_methods #=> ["a", "c"]
Module#private_class_method
[править]mod.private_class_method(symbol, ...) => mod
Makes existing class methods private. Often used to hide the default constructor new.
class SimpleSingleton # Not thread safe
private_class_method :new
def SimpleSingleton.create(*args, &block)
@me = new(*args, &block) if ! @me
@me
end
end
Module#private_instance_methods
[править]mod.private_instance_methods(include_super=true) => array
Returns a list of the private instance methods defined in mod. If the optional parameter is not false, the methods of any ancestors are included.
module Mod
def method1() end
private :method1
def method2() end
end
Mod.instance_methods #=> ["method2"]
Mod.private_instance_methods #=> ["method1"]
Module#private_method_defined?
[править]mod.private_method_defined?(symbol) => true or false
Returns true if the named private method is defined by _ mod_ (or its included modules and, if mod is a class, its ancestors).
module A
def method1() end
end
class B
private
def method2() end
end
class C < B
include A
def method3() end
end
A.method_defined? :method1 #=> true
C.private_method_defined? "method1" #=> false
C.private_method_defined? "method2" #=> true
C.method_defined? "method2" #=> false
Module#protected
[править]protected => self protected(symbol, ...) => self
With no arguments, sets the default visibility for subsequently defined methods to protected. With arguments, sets the named methods to have protected visibility.
Module#protected_instance_methods
[править]mod.protected_instance_methods(include_super=true) => array
Returns a list of the protected instance methods defined in mod. If the optional parameter is not false, the methods of any ancestors are included.
Module#protected_method_defined?
[править]mod.protected_method_defined?(symbol) => true or false
Returns true if the named protected method is defined by mod (or its included modules and, if mod is a class, its ancestors).
module A
def method1() end
end
class B
protected
def method2() end
end
class C < B
include A
def method3() end
end
A.method_defined? :method1 #=> true
C.protected_method_defined? "method1" #=> false
C.protected_method_defined? "method2" #=> true
C.method_defined? "method2" #=> true
Module#public
[править]public => self public(symbol, ...) => self
With no arguments, sets the default visibility for subsequently defined methods to public. With arguments, sets the named methods to have public visibility.
Module#public_class_method
[править]mod.public_class_method(symbol, ...) => mod
Makes a list of existing class methods public.
Module#public_instance_methods
[править]mod.public_instance_methods(include_super=true) => array
Returns a list of the public instance methods defined in mod. If the optional parameter is not false, the methods of any ancestors are included.
Module#public_method_defined?
[править]mod.public_method_defined?(symbol) => true or false
Returns true if the named public method is defined by mod (or its included modules and, if mod is a class, its ancestors).
module A
def method1() end
end
class B
protected
def method2() end
end
class C < B
include A
def method3() end
end
A.method_defined? :method1 #=> true
C.public_method_defined? "method1" #=> true
C.public_method_defined? "method2" #=> false
C.method_defined? "method2" #=> true
Module#remove_class_variable
[править]remove_class_variable(sym) => obj
Removes the definition of the sym, returning that constant's value.
class Dummy
@@var = 99
puts @@var
remove_class_variable(:@@var)
puts(defined? @@var)
end
produces:
99
nil
Module#remove_const
[править]remove_const(sym) => obj
Removes the definition of the given constant, returning that constant's value. Predefined classes and singleton objects (such as true) cannot be removed.
Module#remove_method
[править]remove_method(symbol) => self
Removes the method identified by symbol from the current class. For an example, see Module.undef_method.
Module#to_s
[править]mod.to_s => string
Return a string representing this module or class. For basic classes and modules, this is the name. For singletons, we show information on the thing we're attached to as well.
Module#undef_method
[править]undef_method(symbol) => self
Prevents the current class from responding to calls to the named method. Contrast this with remove_method, which deletes the method from the particular class; Ruby will still search superclasses and mixed-in modules for a possible receiver.
class Parent
def hello
puts "In parent"
end
end
class Child < Parent
def hello
puts "In child"
end
end
c = Child.new
c.hello
class Child
remove_method :hello # remove from child, still in parent
end
c.hello
class Child
undef_method :hello # prevent any calls to 'hello'
end
c.hello
produces:
In child
In parent
prog.rb:23: undefined method `hello' for #<Child:0x401b3bb4> (NoMethodError)