Ruby/Справочник/Object

Класс Object

Object is the parent class of all classes in Ruby. Its methods are therefore available to all objects unless explicitly overridden. Object mixes in the Kernel module, making the built-in kernel functions globally accessible. Although the instance methods of Object are defined by the Kernel module, we have chosen to document them here for clarity. In the descriptions of Object's methods, the parameter symbol refers to a symbol, which is either a quoted string or a Symbol (such as :name).

Same as above, except in Object.

metaprogramming assistant -- metaid.rb

Примеси

Kernel (Array, Float, Integer, Pathname, String, URI, `, abort, at_exit, autoload, autoload?, binding, block_given?, callcc, caller, catch, chomp, chomp!, chop, chop!, eval, exec, exit, exit!, fail, fork, format, gem, getc, gets, global_variables, gsub, gsub!, iterator?, lambda, load, local_variables, loop, method_missing, open, open_uri_original_open, p, pp, pretty_inspect, print, printf, proc, putc, puts, raise, rake_dup, rand, readline, readlines, require, require_gem, scan, scanf, select, set_trace_func, sleep, split, sprintf, srand, sub, sub!, syscall, system, test, throw, to_ptr, trace_var, trap, untrace_var, warn, y),

PP::ObjectMixin (pretty_print, pretty_print_cycle, pretty_print_inspect, pretty_print_instance_variables)

Константы

ARGF, ARGV, DATA, ENV, FALSE, IPsocket, MatchingData, NIL, PLATFORM, RELEASE_DATE, RUBY_PATCHLEVEL, RUBY_PLATFORM, RUBY_RELEASE_DATE, RUBY_VERSION, SOCKSsocket, STDERR, STDIN, STDOUT, TCPserver, TCPsocket, TOPLEVEL_BINDING, TRUE, UDPsocket, UNIXserver, UNIXsocket, VERSION

Методы класса

find_hidden_method, method_added, new

Методы объекта

===, ==, =~, __id__, __send__, class_def, class, clone, dclone, display, dup, enum_for, eql?, equal?, extend, freeze, frozen?, hash, id, inspect, instance_eval, instance_of?, instance_variable_get, instance_variable_set, instance_variables, is_a?, kind_of?, meta_def, meta_eval, metaclass, methods, method, nil?, object_id, private_methods, protected_methods, public_methods, remove_instance_variable, respond_to?, send, singleton_method_added, singleton_method_removed, singleton_method_undefined, singleton_methods, tainted?, taint, to_a, to_enum, to_s, to_yaml_properties, to_yaml_style, to_yaml, type, untaint

Object::find_hidden_method

 Object::find_hidden_method(name)

(нет описания...)

Object::method_added

 Object::method_added(name)

Detect method additions to Object and remove them in the BlankSlate class.

Object::new

 Object::new()

Not documented

Object#==

 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

Object#===

 obj === other   => true or false

Case Equality---For class Object, effectively the same as calling #==, but typically overridden by descendents to provide meaningful semantics in case statements.

Object#=~

 obj =~ other  => false

Pattern Match---Overridden by descendents (notably Regexp and String) to provide meaningful pattern-match semantics.

Object#id

 obj.__id__       => fixnum
 obj.object_id    => fixnum

Document-method: object_id Returns an integer identifier for obj. The same number will be returned on all calls to id for a given object, and no two active objects will share an id. Object#object_id is a different concept from the :name notation, which returns the symbol id of name. Replaces the deprecated Object#id.

Object#send

 obj.send(symbol [, args...])        => obj
 obj.__send__(symbol [, args...])    => obj

Invokes the method identified by symbol, passing it any arguments specified. You can use __send__ if the name send clashes with an existing method in obj.

  class Klass
    def hello(*args)
      "Hello " + args.join(' ')
    end
  end
  k = Klass.new
  k.send :hello, "gentle", "readers"   #=> "Hello gentle readers"

Object#class

 obj.class    => class

Returns the class of obj, now preferred over Object#type, as an object's type in Ruby is only loosely tied to that object's class. This method must always be called with an explicit receiver, as class is also a reserved word in Ruby.

  1.class      #=> Fixnum
  self.class   #=> Object

Object#class_def

 class_def(name, &blk)

Defines an instance method within a class

Object#clone

 obj.clone -> an_object

Produces a shallow copy of obj---the instance variables of obj are copied, but not the objects they reference. Copies the frozen and tainted state of obj. See also the discussion under Object#dup.

  class Klass
     attr_accessor :str
  end
  s1 = Klass.new      #=> #<Klass:0x401b3a38>
  s1.str = "Hello"    #=> "Hello"
  s2 = s1.clone       #=> #<Klass:0x401b3998 @str="Hello">
  s2.str[1,4] = "i"   #=> "i"
  s1.inspect          #=> "#<Klass:0x401b3a38 @str=\"Hi\">"
  s2.inspect          #=> "#<Klass:0x401b3998 @str=\"Hi\">"

This method may have class-specific behavior. If so, that behavior will be documented under the #initialize_copy method of the class.

Object#dclone

 dclone()

(нет описания...)

Object#display

 obj.display(port=$>)    => nil

Prints obj on the given port (default $>). Equivalent to:

  def display(port=$>)
    port.write self
  end

For example:

  1.display
  "cat".display
  [ 4, 5, 6 ].display
  puts

produces:

  1cat456

Object#dup

 obj.dup -> an_object

Produces a shallow copy of obj---the instance variables of obj are copied, but not the objects they reference. dup copies the tainted state of obj. See also the discussion under Object#clone. In general, clone and dup may have different semantics in descendent classes. While clone is used to duplicate an object, including its internal state, dup typically uses the class of the descendent object to create the new instance. This method may have class-specific behavior. If so, that behavior will be documented under the #initialize_copy method of the class.

Object#enum_for

 obj.to_enum(method = :each, *args)
 obj.enum_for(method = :each, *args)

Returns Enumerable::Enumerator.new(self, method, *args). e.g.:

  str = "xyz"

  enum = str.enum_for(:each_byte)
  a = enum.map {|b| '%02x' % b } #=> ["78", "79", "7a"]

  # protects an array from being modified
  a = [1, 2, 3]
  some_method(a.to_enum)

Object#eql?

 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

Object#equal?

 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

Object#extend

 obj.extend(module, ...)    => obj

Adds to obj the instance methods from each module given as a parameter.

  module Mod
    def hello
      "Hello from Mod.\n"
    end
  end

  class Klass
    def hello
      "Hello from Klass.\n"
    end
  end

  k = Klass.new
  k.hello         #=> "Hello from Klass.\n"
  k.extend(Mod)   #=> #<Klass:0x401b3bc8>
  k.hello         #=> "Hello from Mod.\n"

Object#freeze

 obj.freeze    => obj

Prevents further modifications to obj. A TypeError will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?.

  a = [ "a", "b", "c" ]
  a.freeze
  a << "z"

produces:

  prog.rb:3:in `<<': can't modify frozen array (TypeError)
   from prog.rb:3

Object#frozen?

 obj.frozen?    => true or false

Returns the freeze status of obj.

  a = [ "a", "b", "c" ]
  a.freeze    #=> ["a", "b", "c"]
  a.frozen?   #=> true

Object#hash

 obj.hash    => fixnum

Generates a Fixnum hash value for this object. This function must have the property that a.eql?(b) implies a.hash == b.hash. The hash value is used by class Hash. Any hash value that exceeds the capacity of a Fixnum will be truncated before being used.

Object#id

 obj.id    => fixnum

Soon-to-be deprecated version of Object#object_id.

Object#inspect

 obj.inspect   => string

Returns a string containing a human-readable representation of obj. If not overridden, uses the to_s method to generate the string.

  [ 1, 2, 3..4, 'five' ].inspect   #=> "[1, 2, 3..4, \"five\"]"
  Time.new.inspect                 #=> "Wed Apr 09 08:54:39 CDT 2003"

Object#instance_eval

 obj.instance_eval(string [, filename [, lineno]] )   => obj
 obj.instance_eval {| | block }                       => obj

Evaluates a string containing Ruby source code, or the given block, within the context of the receiver (obj). In order to set the context, the variable self is set to obj while the code is executing, giving the code access to obj's instance variables. In the version of instance_eval that takes a String, the optional second and third parameters supply a filename and starting line number that are used when reporting compilation errors.

  class Klass
    def initialize
      @secret = 99
    end
  end
  k = Klass.new
  k.instance_eval { @secret }   #=> 99

Object#instance_of?

 obj.instance_of?(class)    => true or false

Returns true if obj is an instance of the given class. See also Object#kind_of?.

Object#instance_variable_get

 instance_variable_get(ivarname)

(нет описания...)

Object#instance_variable_set

 instance_variable_set(ivarname, value)

(нет описания...)

Object#instance_variables

 obj.instance_variables    => array

Returns an array of instance variable names for the receiver. Note that simply defining an accessor does not create the corresponding instance variable.

  class Fred
    attr_accessor :a1
    def initialize
      @iv = 3
    end
  end
  Fred.new.instance_variables   #=> ["@iv"]

Object#is_a?

 obj.is_a?(class)       => true or false
 obj.kind_of?(class)    => true or false

Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

  module M;    end
  class A
    include M
  end
  class B < A; end
  class C < B; end
  b = B.new
  b.instance_of? A   #=> false
  b.instance_of? B   #=> true
  b.instance_of? C   #=> false
  b.instance_of? M   #=> false
  b.kind_of? A       #=> true
  b.kind_of? B       #=> true
  b.kind_of? C       #=> false
  b.kind_of? M       #=> true

Object#kind_of?

 obj.is_a?(class)       => true or false
 obj.kind_of?(class)    => true or false

Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

  module M;    end
  class A
    include M
  end
  class B < A; end
  class C < B; end
  b = B.new
  b.instance_of? A   #=> false
  b.instance_of? B   #=> true
  b.instance_of? C   #=> false
  b.instance_of? M   #=> false
  b.kind_of? A       #=> true
  b.kind_of? B       #=> true
  b.kind_of? C       #=> false
  b.kind_of? M       #=> true

Object#meta_def

 meta_def(name, &blk)

Adds methods to a metaclass

Object#meta_eval

 meta_eval(&blk;)

(нет описания...)

Object#metaclass

 metaclass()

The hidden singleton lurks behind everyone

Object#method

 obj.method(sym)    => method

Looks up the named method as a receiver in obj, returning a Method object (or raising NameError). The Method object acts as a closure in obj's object instance, so instance variables and the value of self remain available.

  class Demo
    def initialize(n)
      @iv = n
    end
    def hello()
      "Hello, @iv = #{@iv}"
    end
  end

  k = Demo.new(99)
  m = k.method(:hello)
  m.call   #=> "Hello, @iv = 99"

  l = Demo.new('Fred')
  m = l.method("hello")
  m.call   #=> "Hello, @iv = Fred"

Object#methods

 obj.methods    => array

Returns a list of the names of methods publicly accessible in obj. This will include all the methods accessible in obj's ancestors.

  class Klass
    def kMethod()
    end
  end
  k = Klass.new
  k.methods[0..9]    #=> ["kMethod", "freeze", "nil?", "is_a?",
                          "class", "instance_variable_set",
                           "methods", "extend", "send", "instance_eval"]
  k.methods.length   #=> 42

Object#nil?

 nil?()

call_seq:

 nil.nil?               => true
 <anything_else>.nil?   => false

Only the object nil responds true to nil?.

Object#object_id

 obj.__id__       => fixnum
 obj.object_id    => fixnum

Returns an integer identifier for obj. The same number will be returned on all calls to id for a given object, and no two active objects will share an id. Object#object_id is a different concept from the :name notation, which returns the symbol id of name. Replaces the deprecated Object#id.

Object#private_methods

 obj.private_methods(all=true)   => array

Returns the list of private methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

Object#protected_methods

 obj.protected_methods(all=true)   => array

Returns the list of protected methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

Object#public_methods

 obj.public_methods(all=true)   => array

Returns the list of public methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

Object#remove_instance_variable

 obj.remove_instance_variable(symbol)    => obj

Removes the named instance variable from obj, returning that variable's value.

  class Dummy
    attr_reader :var
    def initialize
      @var = 99
    end
    def remove
      remove_instance_variable(:@var)
    end
  end
  d = Dummy.new
  d.var      #=> 99
  d.remove   #=> 99
  d.var      #=> nil

Object#respond_to?

 obj.respond_to?(symbol, include_private=false) => true or false

Возвращает значение true, если объект отвечает на данный метод. Частные методы включены в поиск только тогда, когда необязательный второй параметр вычисляется как true.

Object#send

 obj.send(symbol [, args...])        => obj
 obj.__send__(symbol [, args...])    => obj

Invokes the method identified by symbol, passing it any arguments specified. You can use __send__ if the name send clashes with an existing method in obj.

  class Klass
    def hello(*args)
      "Hello " + args.join(' ')
    end
  end
  k = Klass.new
  k.send :hello, "gentle", "readers"   #=> "Hello gentle readers"

Object#singleton_method_added

 singleton_method_added(symbol)

Invoked as a callback whenever a singleton method is added to the receiver.

  module Chatty
    def Chatty.singleton_method_added(id)
      puts "Adding #{id.id2name}"
    end
    def self.one()     end
    def two()          end
    def Chatty.three() end
  end

produces:

  Adding singleton_method_added
  Adding one
  Adding three

Object#singleton_method_removed

 singleton_method_removed(symbol)

Invoked as a callback whenever a singleton method is removed from the receiver.

  module Chatty
    def Chatty.singleton_method_removed(id)
      puts "Removing #{id.id2name}"
    end
    def self.one()     end
    def two()          end
    def Chatty.three() end
    class <<self
      remove_method :three
      remove_method :one
    end
  end

produces:

  Removing three
  Removing one

Object#singleton_method_undefined

 singleton_method_undefined(symbol)

Invoked as a callback whenever a singleton method is undefined in the receiver.

  module Chatty
    def Chatty.singleton_method_undefined(id)
      puts "Undefining #{id.id2name}"
    end
    def Chatty.one()   end
    class << self
       undef_method(:one)
    end
  end

produces:

  Undefining one

Object#singleton_methods

 obj.singleton_methods(all=true)    => array

Returns an array of the names of singleton methods for obj. If the optional all parameter is true, the list will include methods in modules included in obj.

  module Other
    def three() end
  end

  class Single
    def Single.four() end
  end

  a = Single.new

  def a.one()
  end

  class << a
    include Other
    def two()
    end
  end

  Single.singleton_methods    #=> ["four"]
  a.singleton_methods(false)  #=> ["two", "one"]
  a.singleton_methods         #=> ["two", "one", "three"]

Object#taint

 obj.taint -> obj

Marks obj as tainted---if the $SAFE level is set appropriately, many method calls which might alter the running programs environment will refuse to accept tainted strings.

Object#tainted?

 obj.tainted?    => true or false

Returns true if the object is tainted.

Object#to_a

 obj.to_a -> anArray

Returns an array representation of obj. For objects of class Object and others that don't explicitly override the method, the return value is an array containing self. However, this latter behavior will soon be obsolete.

  self.to_a       #=> -:1: warning: default `to_a' will be obsolete
  "hello".to_a    #=> ["hello"]
  Time.new.to_a   #=> [39, 54, 8, 9, 4, 2003, 3, 99, true, "CDT"]

Object#to_enum

 obj.to_enum(method = :each, *args)
 obj.enum_for(method = :each, *args)

Returns Enumerable::Enumerator.new(self, method, *args). e.g.:

  str = "xyz"

  enum = str.enum_for(:each_byte)
  a = enum.map {|b| '%02x' % b } #=> ["78", "79", "7a"]

  # protects an array from being modified
  a = [1, 2, 3]
  some_method(a.to_enum)

Object#to_s

 obj.to_s    => string

Returns a string representing obj. The default to_s prints the object's class and an encoding of the object id. As a special case, the top-level object that is the initial execution context of Ruby programs returns ``main.

Object#type

 obj.type   => class

Deprecated synonym for Object#class.

Object#untaint

 obj.untaint    => obj

Removes the taint from obj.

Класс Object

Object::find_hidden_method

Object::method_added

Object::new

Object#==

Object#===

Object#=~

Object#__id__

Object#__send__

Object#class

Object#class_def

Object#clone

Object#dclone

Object#display

Object#dup

Object#enum_for

Object#eql?

Object#equal?

Object#extend

Object#freeze

Object#frozen?

Object#hash

Object#id

Object#inspect

Object#instance_eval

Object#instance_of?

Object#instance_variable_get

Object#instance_variable_set

Object#instance_variables

Object#is_a?

Object#kind_of?

Object#meta_def

Object#meta_eval

Object#metaclass

Object#method

Object#methods

Object#nil?

Object#object_id

Object#private_methods

Object#protected_methods

Object#public_methods

Object#remove_instance_variable

Object#respond_to?

Object#send

Object#singleton_method_added

Object#singleton_method_removed

Object#singleton_method_undefined

Object#singleton_methods

Object#taint

Object#tainted?

Object#to_a

Object#to_enum

Object#to_s

Object#type

Object#untaint

Object#id

Object#send