Class: Object
Relationships & Source Files | |
Super Chains via Extension / Inclusion / Inheritance | |
Instance Chain:
self,
::Kernel
|
|
Inherits: | BasicObject |
Defined in: | class.c, enumerator.c, eval.c, gc.c, hash.c, io.c, object.c, proc.c, variable.c, vm_eval.c, vm_method.c |
Overview
Object
is the default root of all Ruby objects. Object
inherits from ::BasicObject
which allows creating alternate object hierarchies. Methods on Object
are available to all classes 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.
When referencing constants in classes inheriting from Object
you do not need to use the full namespace. For example, referencing ::File
inside YourClass
will find the top-level ::File
class.
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
).
What’s Here
First, what’s elsewhere. Class Object:
-
Inherits from
class Basic
. -
Includes
module Kernel
.
Here, class Object provides methods for:
-
Querying
-
Instance Variables
-
Other
Querying
-
#!~: Returns
true
ifself
does not match the given object, otherwisefalse
. -
#<=>: Returns 0 if
self
and the given objectobject
are the same object, or ifself == object
; otherwise returnsnil
. -
#===: Implements case equality, effectively the same as calling
#==
. -
#eql?: Implements hash equality, effectively the same as calling
#==
. -
#kind_of? (aliased as #is_a?): Returns whether given argument is an ancestor of the singleton class of
self
. -
#instance_of?: Returns whether
self
is an instance of the given class. -
#instance_variable_defined?: Returns whether the given instance variable is defined in
self
. -
#method: Returns the
::Method
object for the given method inself
. -
#methods: Returns an array of symbol names of public and protected methods in
self
. -
#nil?: Returns
false
. (Onlynil
respondstrue
to method #nil?.) -
#object_id: Returns an integer corresponding to
self
that is unique for the current process -
#private_methods: Returns an array of the symbol names of the private methods in
self
. -
#protected_methods: Returns an array of the symbol names of the protected methods in
self
. -
#public_method: Returns the
::Method
object for the given public method inself
. -
#public_methods: Returns an array of the symbol names of the public methods in
self
. -
#respond_to?: Returns whether
self
responds to the given method. -
#singleton_class: Returns the singleton class of
self
. -
#singleton_method: Returns the
::Method
object for the given singleton method inself
. -
#singleton_methods: Returns an array of the symbol names of the singleton methods in
self
. -
#define_singleton_method: Defines a singleton method in
self
for the given symbol method-name and block or proc. -
#extend: Includes the given modules in the singleton class of
self
. -
#public_send: Calls the given public method in
self
with the given argument. -
#send: Calls the given method in
self
with the given argument.
Instance Variables
-
#instance_variable_get: Returns the value of the given instance variable in
self
, ornil
if the instance variable is not set. -
#instance_variable_set: Sets the value of the given instance variable in
self
to the given object. -
#instance_variables: Returns an array of the symbol names of the instance variables in
self
. -
#remove_instance_variable: Removes the named instance variable from
self
.
Other
-
#clone
: Returns a shallow copy ofself
, including singleton class and frozen state. -
#define_singleton_method: Defines a singleton method in
self
for the given symbol method-name and block or proc. -
#dup: Returns a shallow unfrozen copy of
self
. -
#enum_for (aliased as #to_enum): Returns an
::Enumerator
forself
using the using the given method, arguments, and block. -
#extend: Includes the given modules in the singleton class of
self
. -
#freeze: Prevents further modifications to
self
. -
#hash: Returns the integer hash value for
self
. -
#inspect: Returns a human-readable string representation of
self
. -
#itself: Returns
self
. -
#method_missing
:::Method
called when an undefined method is called onself
. -
#public_send: Calls the given public method in
self
with the given argument. -
#send: Calls the given method in
self
with the given argument. -
#to_s: Returns a string representation of
self
.
Instance Attribute Summary
-
#nil? ⇒ Boolean
readonly
Only the object nil responds
true
tonil?
.
::Kernel
- Included
#frozen? | Returns the freeze status of obj. |
Instance Method Summary
-
#!~(other) ⇒ Boolean
Returns true if two objects do not match (using the =~ method), otherwise false.
-
#<=>(other) ⇒ 0?
Returns 0 if
obj
andother
are the same object orobj == other
, otherwise nil. - #===
-
#define_singleton_method(symbol, method) ⇒ Symbol
Defines a public singleton method in the receiver.
-
#display(port = $>) ⇒ nil
Writes
self
on the given port: -
#dup ⇒ Object
Produces a shallow copy of obj—the instance variables of obj are copied, but not the objects they reference.
-
#enum_for(method = :each, *args) ⇒ Enumerator
Alias for #to_enum.
-
#eql?(other) ⇒ Boolean
Alias for BasicObject#==.
-
#extend(module, ...) ⇒ Object
Adds to obj the instance methods from each module given as a parameter.
-
#freeze ⇒ Object
Prevents further modifications to obj.
-
#hash ⇒ Integer
Generates an
::Integer
hash value for this object. -
#inspect ⇒ String
Returns a string containing a human-readable representation of obj.
-
#instance_of?(class) ⇒ Boolean
Returns
true
if obj is an instance of the given class. -
#instance_variable_defined?(symbol) ⇒ Boolean
Returns
true
if the given instance variable is defined in obj. -
#instance_variable_get(symbol) ⇒ Object
Returns the value of the given instance variable, or nil if the instance variable is not set.
-
#instance_variable_set(symbol, obj) ⇒ Object
Sets the instance variable named by symbol to the given object.
-
#instance_variables ⇒ Array
Returns an array of instance variable names for the receiver.
-
#is_a?(class) ⇒ Boolean
(also: #kind_of?)
Returns
true
if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj. -
#itself ⇒ Object
Returns the receiver.
-
#kind_of?(class) ⇒ Boolean
Alias for #is_a?.
-
#method(sym) ⇒ method
Looks up the named method as a receiver in obj, returning a
::Method
object (or raising::NameError
). -
#methods(regular = true) ⇒ Array
Returns a list of the names of public and protected methods of obj.
-
#object_id ⇒ Integer
Alias for BasicObject#__id__.
-
#private_methods(all = true) ⇒ Array
Returns the list of private methods accessible to obj.
-
#protected_methods(all = true) ⇒ Array
Returns the list of protected methods accessible to obj.
-
#public_method(sym) ⇒ method
Similar to method, searches public method only.
-
#public_methods(all = true) ⇒ Array
Returns the list of public methods accessible to obj.
-
#public_send(symbol [, args...]) ⇒ Object
Invokes the method identified by symbol, passing it any arguments specified.
-
#remove_instance_variable(symbol) ⇒ Object
Removes the named instance variable from obj, returning that variable’s value.
-
#respond_to?(symbol, include_all = false) ⇒ Boolean
Returns
true
if obj responds to the given method. -
#respond_to_missing?(symbol, include_all) ⇒ Boolean
DO NOT USE THIS DIRECTLY.
-
#send(symbol [, args...]) ⇒ Object
Alias for BasicObject#__send__.
-
#singleton_class ⇒ class
Returns the singleton class of obj.
-
#singleton_method(sym) ⇒ method
Similar to method, searches singleton method only.
-
#singleton_methods(all = true) ⇒ Array
Returns an array of the names of singleton methods for obj.
-
#to_enum(method = :each, *args) ⇒ Enumerator
(also: #enum_for)
Creates a new
::Enumerator
which will enumerate by calling #method onobj
, passingargs
if any. -
#to_s ⇒ String
Returns a string representing obj.
- #initialize_clone(*args) Internal use only
- #initialize_copy(orig) Internal use only
- #initialize_dup(orig) Internal use only
::Kernel
- Included
#class | Returns the class of obj. |
#clone | Produces a shallow copy of obj—the instance variables of obj are copied, but not the objects they reference. |
#tap | Yields self to the block and then returns self. |
#then | Yields self to the block and returns the result of the block. |
#yield_self | Alias for Kernel#then. |
#Float | Returns arg converted to a float. |
#Integer | Returns an integer converted from |
#loop | Repeatedly executes the block. |
#pp | Alias for Kernel#pp. |
#warn | If warnings have been disabled (for example with the |
#with_yjit | Internal helper for built-in initializations to define methods only when YJIT is enabled. |
Instance Attribute Details
#nil? ⇒ Boolean
(readonly)
Only the object nil responds true
to nil?
.
Object.new.nil? #=> false
nil.nil? #=> true
# File 'object.c', line 1659
VALUE rb_false(VALUE obj) { return Qfalse; }
Instance Method Details
#!~(other) ⇒ Boolean
Returns true if two objects do not match (using the =~ method), otherwise false.
# File 'object.c', line 1673
static VALUE rb_obj_not_match(VALUE obj1, VALUE obj2) { VALUE result = rb_funcall(obj1, id_match, 1, obj2); return rb_obj_not(result); }
#<=>(other) ⇒ 0
?
Returns 0 if obj
and other
are the same object or obj == other
, otherwise nil.
The #<=>
is used by various methods to compare objects, for example Enumerable#sort, Enumerable#max etc.
Your implementation of #<=>
should return one of the following values: -1, 0, 1 or nil. -1 means self is smaller than other. 0 means self is equal to other. 1 means self is bigger than other. Nil means the two values could not be compared.
When you define #<=>
, you can include ::Comparable
to gain the methods #<=
, #<
, #==
, #>=
, #>
and #between?
.
# File 'object.c', line 1699
static VALUE rb_obj_cmp(VALUE obj1, VALUE obj2) { if (rb_equal(obj1, obj2)) return INT2FIX(0); return Qnil; }
#===
[ GitHub ]Defines a public singleton method in the receiver. The method parameter can be a ::Proc
, a ::Method
or an ::UnboundMethod
object. If a block is specified, it is used as the method body. If a block or a method has parameters, they’re used as method parameters.
class A
class << self
def class_name
to_s
end
end
end
A.define_singleton_method(:who_am_i) do
"I am: #{class_name}"
end
A.who_am_i # ==> "I am: A"
guy = "Bob"
guy.define_singleton_method(:hello) { "#{self}: Hello there!" }
guy.hello #=> "Bob: Hello there!"
chris = "Chris"
chris.define_singleton_method(:greet) {|greeting| "#{greeting}, I'm Chris!" }
chris.greet("Hi") #=> "Hi, I'm Chris!"
# File 'proc.c', line 2357
static VALUE rb_obj_define_method(int argc, VALUE *argv, VALUE obj) { VALUE klass = rb_singleton_class(obj); const rb_scope_visibility_t scope_visi = {METHOD_VISI_PUBLIC, FALSE}; return rb_mod_define_method_with_visibility(argc, argv, klass, &scope_visi); }
#display(port = $>) ⇒ nil
Writes self
on the given port:
1.display
"cat".display
[ 4, 5, 6 ].display
puts
Output:
1cat[4, 5, 6]
# File 'io.c', line 9083
static VALUE rb_obj_display(int argc, VALUE *argv, VALUE self) { VALUE out; out = (!rb_check_arity(argc, 0, 1) ? rb_ractor_stdout() : argv[0]); rb_io_write(out, self); return Qnil; }
#dup ⇒ Object
Produces a shallow copy of obj—the instance variables of obj are copied, but not the objects they reference.
This method may have class-specific behavior. If so, that behavior will be documented under the #initialize_copy
method of the class.
on dup vs clone
In general, #clone
and #dup
may have different semantics in descendant classes. While #clone
is used to duplicate an object, including its internal state, #dup
typically uses the class of the descendant object to create the new instance.
When using #dup
, any modules that the object has been extended with will not be copied.
class Klass
attr_accessor :str
end
module Foo
def foo; 'foo'; end
end
s1 = Klass.new #=> #<Klass:0x401b3a38>
s1.extend(Foo) #=> #<Klass:0x401b3a38>
s1.foo #=> "foo"
s2 = s1.clone #=> #<Klass:0x401be280>
s2.foo #=> "foo"
s3 = s1.dup #=> #<Klass:0x401c1084>
s3.foo #=> NoMethodError: undefined method `foo' for #<Klass:0x401c1084>
# File 'object.c', line 625
VALUE rb_obj_dup(VALUE obj) { VALUE dup; if (special_object_p(obj)) { return obj; } dup = rb_obj_alloc(rb_obj_class(obj)); return rb_obj_dup_setup(obj, dup); }
#to_enum(method = :each, *args) ⇒ Enumerator
#enum_for(method = :each, *args) ⇒ Enumerator
#to_enum(method = :each, *args) {|*args| ... } ⇒ Enumerator
#enum_for(method = :each, *args) {|*args| ... } ⇒ Enumerator
Alias for #to_enum.
#eql?(other) ⇒ Boolean
Alias for BasicObject#==.
#extend(module, ...) ⇒ Object
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"
# File 'eval.c', line 1799
static VALUE rb_obj_extend(int argc, VALUE *argv, VALUE obj) { int i; ID id_extend_object, id_extended; CONST_ID(id_extend_object, "extend_object"); CONST_ID(id_extended, "extended"); rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS); for (i = 0; i < argc; i++) { Check_Type(argv[i], T_MODULE); if (FL_TEST(argv[i], RMODULE_IS_REFINEMENT)) { rb_raise(rb_eTypeError, "Cannot extend object with refinement"); } } while (argc--) { rb_funcall(argv[argc], id_extend_object, 1, obj); rb_funcall(argv[argc], id_extended, 1, obj); } return obj; }
#freeze ⇒ Object
Prevents further modifications to obj. A ::FrozenError
will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?
.
This method returns self.
a = [ "a", "b", "c" ]
a.freeze
a << "z"
produces:
prog.rb:3:in `<<': can't modify frozen Array (FrozenError)
from prog.rb:3
Objects of the following classes are always frozen: ::Integer
, ::Float
, ::Symbol
.
# File 'object.c', line 1318
VALUE rb_obj_freeze(VALUE obj) { if (!OBJ_FROZEN(obj)) { OBJ_FREEZE(obj); if (SPECIAL_CONST_P(obj)) { rb_bug("special consts should be frozen."); } } return obj; }
#hash ⇒ Integer
Generates an ::Integer
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 along with #eql? by the ::Hash
class to determine if two objects reference the same hash key. Any hash value that exceeds the capacity of an ::Integer
will be truncated before being used.
The hash value for an object may not be identical across invocations or implementations of Ruby. If you need a stable identifier across Ruby invocations and implementations you will need to generate one with a custom method.
Certain core classes such as ::Integer
use built-in hash calculations and do not call the #hash
method when used as a hash key.
When implementing your own #hash
based on multiple values, the best practice is to combine the class and any values using the hash code of an array:
For example:
def hash
[self.class, a, b, c].hash
end
The reason for this is that the Array#hash method already has logic for safely and efficiently combining multiple hash values.
# File 'hash.c', line 363
VALUE rb_obj_hash(VALUE obj) { long hnum = any_hash(obj, objid_hash); return ST2FIX(hnum); }
#initialize_clone(*args)
# File 'object.c', line 705
static VALUE rb_obj_init_clone(int argc, VALUE *argv, VALUE obj) { VALUE orig, opts; if (rb_scan_args(argc, argv, "1:", &orig, &opts) < argc) { /* Ignore a freeze keyword */ rb_get_freeze_opt(1, &opts); } rb_funcall(obj, id_init_copy, 1, orig); return obj; }
#initialize_copy(orig)
# File 'object.c', line 668
VALUE rb_obj_init_copy(VALUE obj, VALUE orig) { if (obj == orig) return obj; rb_check_frozen(obj); if (TYPE(obj) != TYPE(orig) || rb_obj_class(obj) != rb_obj_class(orig)) { rb_raise(rb_eTypeError, "initialize_copy should take same class object"); } return obj; }
#initialize_dup(orig)
# File 'object.c', line 688
VALUE rb_obj_init_dup_clone(VALUE obj, VALUE orig) { rb_funcall(obj, id_init_copy, 1, orig); return obj; }
#inspect ⇒ String
Returns a string containing a human-readable representation of obj. The default #inspect
shows the object’s class name, an encoding of its memory address, and a list of the instance variables and their values (by calling #inspect
on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.
[ 1, 2, 3..4, 'five' ].inspect #=> "[1, 2, 3..4, \"five\"]"
Time.new.inspect #=> "2008-03-08 19:43:39 +0900"
class Foo
end
Foo.new.inspect #=> "#<Foo:0x0300c868>"
class Bar
def initialize
@bar = 1
end
end
Bar.new.inspect #=> "#<Bar:0x0300c868 @bar=1>"
# File 'object.c', line 818
static VALUE rb_obj_inspect(VALUE obj) { if (rb_ivar_count(obj) > 0) { VALUE str; VALUE c = rb_class_name(CLASS_OF(obj)); str = rb_sprintf("-<%"PRIsVALUE":%p", c, (void*)obj); return rb_exec_recursive(inspect_obj, obj, str); } else { return rb_any_to_s(obj); } }
#instance_of?(class) ⇒ Boolean
Returns true
if obj is an instance of the given class. See also #kind_of?.
class A; 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
# File 'object.c', line 867
VALUE rb_obj_is_instance_of(VALUE obj, VALUE c) { c = class_or_module_required(c); return RBOOL(rb_obj_class(obj) == c); }
#instance_variable_defined?(symbol) ⇒ Boolean
#instance_variable_defined?(string) ⇒ Boolean
Boolean
#instance_variable_defined?(string) ⇒ Boolean
Returns true
if the given instance variable is defined in obj. ::String
arguments are converted to symbols.
class Fred
def initialize(p1, p2)
@a, @b = p1, p2
end
end
fred = Fred.new('cat', 99)
fred.instance_variable_defined?(:@a) #=> true
fred.instance_variable_defined?("@b") #=> true
fred.instance_variable_defined?("@c") #=> false
# File 'object.c', line 2976
static VALUE rb_obj_ivar_defined(VALUE obj, VALUE iv) { ID id = id_for_var(obj, iv, instance); if (!id) { return Qfalse; } return rb_ivar_defined(obj, id); }
#instance_variable_get(symbol) ⇒ Object
#instance_variable_get(string) ⇒ Object
Object
#instance_variable_get(string) ⇒ Object
Returns the value of the given instance variable, or nil if the instance variable is not set. The @
part of the variable name should be included for regular instance variables. Throws a ::NameError
exception if the supplied symbol is not valid as an instance variable name. ::String
arguments are converted to symbols.
class Fred
def initialize(p1, p2)
@a, @b = p1, p2
end
end
fred = Fred.new('cat', 99)
fred.instance_variable_get(:@a) #=> "cat"
fred.instance_variable_get("@b") #=> 99
# File 'object.c', line 2914
static VALUE rb_obj_ivar_get(VALUE obj, VALUE iv) { ID id = id_for_var(obj, iv, instance); if (!id) { return Qnil; } return rb_ivar_get(obj, id); }
#instance_variable_set(symbol, obj) ⇒ Object
#instance_variable_set(string, obj) ⇒ Object
Object
#instance_variable_set(string, obj) ⇒ Object
Sets the instance variable named by symbol to the given object. This may circumvent the encapsulation intended by the author of the class, so it should be used with care. The variable does not have to exist prior to this call. If the instance variable name is passed as a string, that string is converted to a symbol.
class Fred
def initialize(p1, p2)
@a, @b = p1, p2
end
end
fred = Fred.new('cat', 99)
fred.instance_variable_set(:@a, 'dog') #=> "dog"
fred.instance_variable_set(:@c, 'cat') #=> "cat"
fred.inspect #=> "#<Fred:0x401b3da8 @a=\"dog\", @b=99, @c=\"cat\">"
# File 'object.c', line 2948
static VALUE rb_obj_ivar_set_m(VALUE obj, VALUE iv, VALUE val) { ID id = id_for_var(obj, iv, instance); if (!id) id = rb_intern_str(iv); return rb_ivar_set(obj, id, val); }
#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]
# File 'variable.c', line 2194
VALUE rb_obj_instance_variables(VALUE obj) { VALUE ary; ary = rb_ary_new(); rb_ivar_foreach(obj, ivar_i, ary); return ary; }
#is_a?(class) ⇒ Boolean
#kind_of?(class) ⇒ Boolean
Also known as: #kind_of?
Boolean
#kind_of?(class) ⇒ Boolean
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.is_a? A #=> true
b.is_a? B #=> true
b.is_a? C #=> false
b.is_a? M #=> true
b.kind_of? A #=> true
b.kind_of? B #=> true
b.kind_of? C #=> false
b.kind_of? M #=> true
# File 'object.c', line 923
VALUE rb_obj_is_kind_of(VALUE obj, VALUE c) { VALUE cl = CLASS_OF(obj); RUBY_ASSERT(RB_TYPE_P(cl, T_CLASS)); // Fastest path: If the object's class is an exact match we know `c` is a // class without checking type and can return immediately. if (cl == c) return Qtrue; // Note: YJIT needs this function to never allocate and never raise when // `c` is a class or a module. if (LIKELY(RB_TYPE_P(c, T_CLASS))) { // Fast path: Both are T_CLASS return class_search_class_ancestor(cl, c); } else if (RB_TYPE_P(c, T_ICLASS)) { // First check if we inherit the includer // If we do we can return true immediately VALUE includer = RCLASS_INCLUDER(c); if (cl == includer) return Qtrue; // Usually includer is a T_CLASS here, except when including into an // already included Module. // If it is a class, attempt the fast class-to-class check and return // true if there is a match. if (RB_TYPE_P(includer, T_CLASS) && class_search_class_ancestor(cl, includer)) return Qtrue; // We don't include the ICLASS directly, so must check if we inherit // the module via another include return RBOOL(class_search_ancestor(cl, RCLASS_ORIGIN(c))); } else if (RB_TYPE_P(c, T_MODULE)) { // Slow path: check each ancestor in the linked list and its method table return RBOOL(class_search_ancestor(cl, RCLASS_ORIGIN(c))); } else { rb_raise(rb_eTypeError, "class or module required"); UNREACHABLE_RETURN(Qfalse); } }
#itself ⇒ Object
[ GitHub ]
# File 'object.c', line 648
static VALUE rb_obj_itself(VALUE obj) { return obj; }
#is_a?(class) ⇒ Boolean
#kind_of?(class) ⇒ Boolean
Boolean
#kind_of?(class) ⇒ Boolean
Alias for #is_a?.
#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"
Note that ::Method
implements to_proc
method, which means it can be used with iterators.
[ 1, 2, 3 ].each(&method(:puts)) # => prints 3 lines to stdout
out = File.open('test.txt', 'w')
[ 1, 2, 3 ].each(&out.method(:puts)) # => prints 3 lines to file
require 'date'
%w[2017-03-01 2017-03-02].collect(&Date.method(:parse))
#=> [#<Date: 2017-03-01 ((2457814j,0s,0n),+0s,2299161j)>, #<Date: 2017-03-02 ((2457815j,0s,0n),+0s,2299161j)>]
# File 'proc.c', line 2047
VALUE rb_obj_method(VALUE obj, VALUE vid) { return obj_method(obj, vid, FALSE); }
#methods(regular = true) ⇒ Array
Returns a list of the names of public and protected methods of obj. This will include all the methods accessible in obj’s ancestors. If the optional parameter is false
, it returns an array of obj’s public and protected singleton methods, the array will not include methods in modules included in obj.
class Klass
def klass_method()
end
end
k = Klass.new
k.methods[0..9] #=> [:klass_method, :nil?, :===,
# :==~, :!, :eql?
# :hash, :<=>, :class, :singleton_class]
k.methods.length #=> 56
k.methods(false) #=> []
def k.singleton_method; end
k.methods(false) #=> [:singleton_method]
module M123; def m123; end end
k.extend M123
k.methods(false) #=> [:singleton_method]
# File 'class.c', line 2002
VALUE rb_obj_methods(int argc, const VALUE *argv, VALUE obj) { rb_check_arity(argc, 0, 1); if (argc > 0 && !RTEST(argv[0])) { return rb_obj_singleton_methods(argc, argv, obj); } return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_i); }
#object_id ⇒ Integer
Alias for BasicObject#__id__.
#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.
# File 'class.c', line 2036
VALUE rb_obj_private_methods(int argc, const VALUE *argv, VALUE obj) { return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_priv_i); }
#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.
# File 'class.c', line 2021
VALUE rb_obj_protected_methods(int argc, const VALUE *argv, VALUE obj) { return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_prot_i); }
#public_method(sym) ⇒ method
Similar to method, searches public method only.
# File 'proc.c', line 2060
VALUE rb_obj_public_method(VALUE obj, VALUE vid) { return obj_method(obj, vid, TRUE); }
#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.
# File 'class.c', line 2051
VALUE rb_obj_public_methods(int argc, const VALUE *argv, VALUE obj) { return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_pub_i); }
#public_send(symbol [, args...]) ⇒ Object
#public_send(string [, args...]) ⇒ Object
Object
#public_send(string [, args...]) ⇒ Object
Invokes the method identified by symbol, passing it any arguments specified. Unlike send, public_send calls public methods only. When the method is identified by a string, the string is converted to a symbol.
1.public_send(:puts, "hello") # causes NoMethodError
# File 'vm_eval.c', line 1327
static VALUE rb_f_public_send(int argc, VALUE *argv, VALUE recv) { return send_internal_kw(argc, argv, recv, CALL_PUBLIC); }
#remove_instance_variable(symbol) ⇒ Object
#remove_instance_variable(string) ⇒ Object
Object
#remove_instance_variable(string) ⇒ Object
Removes the named instance variable from obj, returning that variable’s value. The name can be passed as a symbol or as a string.
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
# File 'variable.c', line 2248
VALUE rb_obj_remove_instance_variable(VALUE obj, VALUE name) { const ID id = id_for_var(obj, name, an, instance); // Frozen check comes here because it's expected that we raise a // NameError (from the id_for_var check) before we raise a FrozenError rb_check_frozen(obj); if (id) { VALUE val = rb_ivar_delete(obj, id, Qundef); if (!UNDEF_P(val)) return val; } rb_name_err_raise("instance variable %1$s not defined", obj, name); UNREACHABLE_RETURN(Qnil); }
#respond_to?(symbol, include_all = false) ⇒ Boolean
#respond_to?(string, include_all = false) ⇒ Boolean
Boolean
#respond_to?(string, include_all = false) ⇒ Boolean
Returns true
if obj responds to the given method. Private and protected methods are included in the search only if the optional second parameter evaluates to true
.
If the method is not implemented, as Process.fork on Windows, File.lchmod on GNU/Linux, etc., false is returned.
If the method is not defined, #respond_to_missing? method is called and the result is returned.
When the method name parameter is given as a string, the string is converted to a symbol.
# File 'vm_method.c', line 2981
static VALUE obj_respond_to(int argc, VALUE *argv, VALUE obj) { VALUE mid, priv; ID id; rb_execution_context_t *ec = GET_EC(); rb_scan_args(argc, argv, "11", &mid, &priv); if (!(id = rb_check_id(&mid))) { VALUE ret = basic_obj_respond_to_missing(ec, CLASS_OF(obj), obj, rb_to_symbol(mid), priv); if (UNDEF_P(ret)) ret = Qfalse; return ret; } return RBOOL(basic_obj_respond_to(ec, obj, id, !RTEST(priv))); }
#respond_to_missing?(symbol, include_all) ⇒ Boolean
#respond_to_missing?(string, include_all) ⇒ Boolean
Boolean
#respond_to_missing?(string, include_all) ⇒ Boolean
DO NOT USE THIS DIRECTLY.
Hook method to return whether the obj can respond to id method or not.
When the method name parameter is given as a string, the string is converted to a symbol.
See #respond_to?, and the example of ::BasicObject
.
# File 'vm_method.c', line 3013
static VALUE obj_respond_to_missing(VALUE obj, VALUE mid, VALUE priv) { return Qfalse; }
#send(symbol [, args...]) ⇒ Object
#send(string [, args...]) ⇒ Object
Object
#send(string [, args...]) ⇒ Object
Alias for BasicObject#__send__. Invokes the method identified by symbol, passing it any arguments specified. When the method is identified by a string, the string is converted to a symbol.
::BasicObject
implements __send__
, ::Kernel
implements send
. __send__
is safer than send
when obj has the same method name like Socket
. See also #public_send.
class Klass
def hello(*args)
"Hello " + args.join(' ')
end
end
k = Klass.new
k.send :hello, "gentle", "readers" #=> "Hello gentle readers"
#singleton_class ⇒ class
Returns the singleton class of obj. This method creates a new singleton class if obj does not have one.
If obj is nil
, true
, or false
, it returns ::NilClass
, ::TrueClass
, or ::FalseClass
, respectively. If obj is an ::Integer
, a ::Float
or a ::Symbol
, it raises a ::TypeError
.
Object.new.singleton_class #=> #<Class:#<Object:0xb7ce1e24>>
String.singleton_class #=> #<Class:String>
nil.singleton_class #=> NilClass
# File 'object.c', line 319
static VALUE rb_obj_singleton_class(VALUE obj) { return rb_singleton_class(obj); }
#singleton_method(sym) ⇒ method
Similar to method, searches singleton method only.
class Demo
def initialize(n)
@iv = n
end
def hello()
"Hello, @iv = #{@iv}"
end
end
k = Demo.new(99)
def k.hi
"Hi, @iv = #{@iv}"
end
m = k.singleton_method(:hi)
m.call #=> "Hi, @iv = 99"
m = k.singleton_method(:hello) #=> NameError
# File 'proc.c', line 2103
VALUE rb_obj_singleton_method(VALUE obj, VALUE vid) { VALUE sc = rb_singleton_class_get(obj); VALUE klass; ID id = rb_check_id(&vid); if (NIL_P(sc) || NIL_P(klass = RCLASS_ORIGIN(sc)) || !NIL_P(rb_special_singleton_class(obj))) { /* goto undef; */ } else if (! id) { VALUE m = mnew_missing_by_name(klass, obj, &vid, FALSE, rb_cMethod); if (m) return m; /* else goto undef; */ } else { VALUE args[2] = {obj, vid}; VALUE ruby_method = rb_rescue(rb_obj_singleton_method_lookup, (VALUE)args, rb_obj_singleton_method_lookup_fail, Qfalse); if (ruby_method) { struct METHOD *method = (struct METHOD *)RTYPEDDATA_GET_DATA(ruby_method); VALUE lookup_class = RBASIC_CLASS(obj); VALUE stop_class = rb_class_superclass(sc); VALUE method_class = method->iclass; /* Determine if method is in singleton class, or module included in or prepended to it */ do { if (lookup_class == method_class) { return ruby_method; } lookup_class = RCLASS_SUPER(lookup_class); } while (lookup_class && lookup_class != stop_class); } } /* undef: */ vid = ID2SYM(id); rb_name_err_raise("undefined singleton method '%1$s' for '%2$s'", obj, vid); UNREACHABLE_RETURN(Qundef); }
#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. Only public and protected singleton methods are returned.
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]
# File 'class.c', line 2090
VALUE rb_obj_singleton_methods(int argc, const VALUE *argv, VALUE obj) { VALUE ary, klass, origin; struct method_entry_arg me_arg; struct rb_id_table *mtbl; int recur = TRUE; if (rb_check_arity(argc, 0, 1)) recur = RTEST(argv[0]); if (RCLASS_SINGLETON_P(obj)) { rb_singleton_class(obj); } klass = CLASS_OF(obj); origin = RCLASS_ORIGIN(klass); me_arg.list = st_init_numtable(); me_arg.recur = recur; if (klass && RCLASS_SINGLETON_P(klass)) { if ((mtbl = RCLASS_M_TBL(origin)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg); klass = RCLASS_SUPER(klass); } if (recur) { while (klass && (RCLASS_SINGLETON_P(klass) || RB_TYPE_P(klass, T_ICLASS))) { if (klass != origin && (mtbl = RCLASS_M_TBL(klass)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg); klass = RCLASS_SUPER(klass); } } ary = rb_ary_new2(me_arg.list->num_entries); st_foreach(me_arg.list, ins_methods_i, ary); st_free_table(me_arg.list); return ary; }
#to_enum(method = :each, *args) ⇒ Enumerator
#enum_for(method = :each, *args) ⇒ Enumerator
#to_enum(method = :each, *args) {|*args| ... } ⇒ Enumerator
#enum_for(method = :each, *args) {|*args| ... } ⇒ Enumerator
Also known as: #enum_for
Creates a new ::Enumerator
which will enumerate by calling #method on obj
, passing args
if any. What was yielded by method becomes values of enumerator.
If a block is given, it will be used to calculate the size of the enumerator without the need to iterate it (see Enumerator#size).
Examples
str = "xyz"
enum = str.enum_for(:each_byte)
enum.each { |b| puts b }
# => 120
# => 121
# => 122
# protect an array from being modified by some_method
a = [1, 2, 3]
some_method(a.to_enum)
# String#split in block form is more memory-effective:
very_large_string.split("|") { |chunk| return chunk if chunk.include?('DATE') }
# This could be rewritten more idiomatically with to_enum:
very_large_string.to_enum(:split, "|").lazy.grep(/DATE/).first
It is typical to call to_enum when defining methods for a generic ::Enumerable
, in case no block is passed.
Here is such an example, with parameter passing and a sizing block:
module Enumerable
# a generic method to repeat the values of any enumerable
def repeat(n)
raise ArgumentError, "#{n} is negative!" if n < 0
unless block_given?
return to_enum(__method__, n) do # __method__ is :repeat here
sz = size # Call size and multiply by n...
sz * n if sz # but return nil if size itself is nil
end
end
each do |*val|
n.times { yield *val }
end
end
end
%i[hello world].repeat(2) { |w| puts w }
# => Prints 'hello', 'hello', 'world', 'world'
enum = (1..14).repeat(3)
# => returns an Enumerator when called without a block
enum.first(4) # => [1, 1, 1, 2]
enum.size # => 42
# File 'enumerator.c', line 381
static VALUE obj_to_enum(int argc, VALUE *argv, VALUE obj) { VALUE enumerator, meth = sym_each; if (argc > 0) { --argc; meth = *argv++; } enumerator = rb_enumeratorize_with_size(obj, meth, argc, argv, 0); if (rb_block_given_p()) { RB_OBJ_WRITE(enumerator, &enumerator_ptr(enumerator)->size, rb_block_proc()); } return enumerator; }
#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”.
# File 'object.c', line 727
VALUE rb_any_to_s(VALUE obj) { VALUE str; VALUE cname = rb_class_name(CLASS_OF(obj)); str = rb_sprintf("#<%"PRIsVALUE":%p>", cname, (void*)obj); return str; }