Class: Object

Inherits:
BasicObject
Includes:
Kernel
Defined in:
object.c,
class.c,
object.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).

Instance Method Summary collapse

Methods included from Kernel

#Array, #Complex, #Float, #Hash, #Integer, #Rational, #String, #__callee__, #__dir__, #__method__, #`, #abort, #at_exit, #autoload, #autoload?, #binding, #block_given?, #callcc, #caller, #caller_locations, #catch, #eval, #exec, #exit, #exit!, #fail, #fork, #format, #gets, #global_variables, #iterator?, #lambda, #load, #local_variables, #loop, #open, #p, #print, #printf, #proc, #putc, #puts, #raise, #rand, #readline, #readlines, #require, #require_relative, #select, #sleep, #spawn, #sprintf, #srand, #syscall, #system, #test, #throw, #trace_var, #trap, #untrace_var, #warn

Instance Method Details

#!~Object

Returns true if two objects do not match (using the =~ method), otherwise false.



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# File 'object.c', line 1310

static VALUE
rb_obj_not_match(VALUE obj1, VALUE obj2)
{
    VALUE result = rb_funcall(obj1, id_match, 1, obj2);
    return RTEST(result) ? Qfalse : Qtrue;
}

#<=>(other) ⇒ 0?

Returns 0 if obj === other, otherwise nil.

Returns:

  • (0, nil)


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# File 'object.c', line 1324

static VALUE
rb_obj_cmp(VALUE obj1, VALUE obj2)
{
    if (obj1 == obj2 || rb_equal(obj1, obj2))
	return INT2FIX(0);
    return Qnil;
}

#===(other) ⇒ Boolean

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

Returns:

  • (Boolean)


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# File 'object.c', line 55

VALUE
rb_equal(VALUE obj1, VALUE obj2)
{
    VALUE result;

    if (obj1 == obj2) return Qtrue;
    result = rb_funcall(obj1, id_eq, 1, obj2);
    if (RTEST(result)) return Qtrue;
    return Qfalse;
}

#=~(other) ⇒ nil

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

Returns:

  • (nil)


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# File 'object.c', line 1296

static VALUE
rb_obj_match(VALUE obj1, VALUE obj2)
{
    return Qnil;
}

#assert_QundefObject

:nodoc:



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# File 'parse.y', line 11326

static VALUE
ripper_assert_Qundef(VALUE self, VALUE obj, VALUE msg)
{
    StringValue(msg);
    if (obj == Qundef) {
        rb_raise(rb_eArgError, "%s", RSTRING_PTR(msg));
    }
    return Qnil;
}

#classClass

Returns the class of obj. 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

Returns:



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# File 'object.c', line 193

VALUE
rb_obj_class(VALUE obj)
{
    return rb_class_real(CLASS_OF(obj));
}

#cloneObject

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.

Returns:



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# File 'object.c', line 295

VALUE
rb_obj_clone(VALUE obj)
{
    VALUE clone;
    VALUE singleton;

    if (rb_special_const_p(obj)) {
        rb_raise(rb_eTypeError, "can't clone %s", rb_obj_classname(obj));
    }
    clone = rb_obj_alloc(rb_obj_class(obj));
    singleton = rb_singleton_class_clone_and_attach(obj, clone);
    RBASIC(clone)->klass = singleton;
    if (FL_TEST(singleton, FL_SINGLETON)) {
	rb_singleton_class_attached(singleton, clone);
    }
    RBASIC(clone)->flags &= (FL_TAINT|FL_UNTRUSTED);
    RBASIC(clone)->flags |= RBASIC(obj)->flags & ~(FL_FREEZE|FL_FINALIZE);
    init_copy(clone, obj);
    rb_funcall(clone, id_init_clone, 1, obj);
    RBASIC(clone)->flags |= RBASIC(obj)->flags & FL_FREEZE;

    return clone;
}

#define_singleton_method(symbol, method) ⇒ Object #define_singleton_method(symbol) { ... } ⇒ Proc

Defines a 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.

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!"

Overloads:

  • #define_singleton_method(symbol) { ... } ⇒ Proc

    Yields:

    Returns:



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# File 'proc.c', line 1444

static VALUE
rb_obj_define_method(int argc, VALUE *argv, VALUE obj)
{
    VALUE klass = rb_singleton_class(obj);

    return rb_mod_define_method(argc, argv, klass);
}

#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

Returns:

  • (nil)


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# File 'io.c', line 6961

static VALUE
rb_obj_display(int argc, VALUE *argv, VALUE self)
{
    VALUE out;

    if (argc == 0) {
	out = rb_stdout;
    }
    else {
	rb_scan_args(argc, argv, "01", &out);
    }
    rb_io_write(out, self);

    return Qnil;
}

#dupObject

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 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.

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

Returns:



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# File 'object.c', line 337

VALUE
rb_obj_dup(VALUE obj)
{
    VALUE dup;

    if (rb_special_const_p(obj)) {
        rb_raise(rb_eTypeError, "can't dup %s", rb_obj_classname(obj));
    }
    dup = rb_obj_alloc(rb_obj_class(obj));
    init_copy(dup, obj);
    rb_funcall(dup, id_init_dup, 1, obj);

    return 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

Creates a new Enumerator which will enumerate by calling method on obj, passing args if any.

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)

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

Overloads:



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# File 'enumerator.c', line 240

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()) {
	enumerator_ptr(enumerator)->size = rb_block_proc();
    }
    return enumerator;
}

#==(other) ⇒ Boolean #equal?(other) ⇒ Boolean #eql?(other) ⇒ Boolean

Equality --- At the Object level, == returns true only if obj and other are the same object. Typically, this method is overridden in descendant classes to provide class-specific meaning.

Unlike ==, the equal? method should never be overridden by subclasses as it is used to determine object identity (that is, a.equal?(b) if and only if a is the same object as b):

obj = "a"
other = obj.dup

a == other      #=> true
a.equal? other  #=> false
a.equal? a      #=> true

The eql? method returns true if obj and other refer to the same hash key. This is used by Hash to test members for equality. For objects of class Object, eql? is synonymous with ==. Subclasses normally continue this tradition by aliasing eql? to their overridden == method, 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

Overloads:

  • #==(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #equal?(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #eql?(other) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 108

VALUE
rb_obj_equal(VALUE obj1, VALUE obj2)
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}

#extendObject

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"

Returns:



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# File 'eval.c', line 1298

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);
    while (argc--) {
	rb_funcall(argv[argc], id_extend_object, 1, obj);
	rb_funcall(argv[argc], id_extended, 1, obj);
    }
    return obj;
}

#freezeObject

Prevents further modifications to obj. A RuntimeError 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 (RuntimeError)
	from prog.rb:3

Returns:



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# File 'object.c', line 969

VALUE
rb_obj_freeze(VALUE obj)
{
    if (!OBJ_FROZEN(obj)) {
	if (rb_safe_level() >= 4 && !OBJ_UNTRUSTED(obj)) {
	    rb_raise(rb_eSecurityError, "Insecure: can't freeze object");
	}
	OBJ_FREEZE(obj);
	if (SPECIAL_CONST_P(obj)) {
	    if (!immediate_frozen_tbl) {
		immediate_frozen_tbl = st_init_numtable();
	    }
	    st_insert(immediate_frozen_tbl, obj, (st_data_t)Qtrue);
	}
    }
    return obj;
}

#frozen?Boolean

Returns the freeze status of obj.

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

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 998

VALUE
rb_obj_frozen_p(VALUE obj)
{
    if (OBJ_FROZEN(obj)) return Qtrue;
    if (SPECIAL_CONST_P(obj)) {
	if (!immediate_frozen_tbl) return Qfalse;
	if (st_lookup(immediate_frozen_tbl, obj, 0)) return Qtrue;
    }
    return Qfalse;
}

#hashObject

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 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 a Fixnum 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.



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# File 'object.c', line 128

VALUE
rb_obj_hash(VALUE obj)
{
    VALUE oid = rb_obj_id(obj);
#if SIZEOF_LONG == SIZEOF_VOIDP
    st_index_t index = NUM2LONG(oid);
#elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
    st_index_t index = NUM2LL(oid);
#else
# error not supported
#endif
    st_index_t h = rb_hash_end(rb_hash_start(index));
    return LONG2FIX(h);
}

#initialize_cloneObject

:nodoc:



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# File 'object.c', line 366

VALUE
rb_obj_init_dup_clone(VALUE obj, VALUE orig)
{
    rb_funcall(obj, id_init_copy, 1, orig);
    return obj;
}

#initialize_copyObject

:nodoc:



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# File 'object.c', line 353

VALUE
rb_obj_init_copy(VALUE obj, VALUE orig)
{
    if (obj == orig) return obj;
    rb_check_frozen(obj);
    rb_check_trusted(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_dupObject

:nodoc:



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# File 'object.c', line 366

VALUE
rb_obj_init_dup_clone(VALUE obj, VALUE orig)
{
    rb_funcall(obj, id_init_copy, 1, orig);
    return obj;
}

#inspectString

Returns a string containing a human-readable representation of obj. By default, show the class name and the list of the instance variables and their values (by calling #inspect on each of them). User defined classes should override this method to make 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>"

class Baz
  def to_s
    "baz"
  end
end
Baz.new.inspect                  #=> "#<Baz:0x0300c868>"

Returns:



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# File 'object.c', line 495

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?Boolean

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

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 544

VALUE
rb_obj_is_instance_of(VALUE obj, VALUE c)
{
    c = class_or_module_required(c);
    if (rb_obj_class(obj) == c) return Qtrue;
    return Qfalse;
}

#instance_variable_defined?(symbol) ⇒ Boolean

Returns true if the given instance variable is defined in obj.

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

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 2163

static VALUE
rb_obj_ivar_defined(VALUE obj, VALUE iv)
{
    ID id = rb_check_id(&iv);

    if (!id) {
	if (rb_is_instance_name(iv)) {
	    return Qfalse;
	}
	else {
	    rb_name_error_str(iv, "`%"PRIsVALUE"' is not allowed as an instance variable name",
			      QUOTE(iv));
	}
    }
    if (!rb_is_instance_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as an instance variable name",
		      QUOTE_ID(id));
    }
    return rb_ivar_defined(obj, id);
}

#instance_variable_get(symbol) ⇒ 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.

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

Returns:



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# File 'object.c', line 2092

static VALUE
rb_obj_ivar_get(VALUE obj, VALUE iv)
{
    ID id = rb_check_id(&iv);

    if (!id) {
	if (rb_is_instance_name(iv)) {
	    return Qnil;
	}
	else {
	    rb_name_error_str(iv, "`%"PRIsVALUE"' is not allowed as an instance variable name",
			      QUOTE(iv));
	}
    }
    if (!rb_is_instance_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as an instance variable name",
		      QUOTE_ID(id));
    }
    return rb_ivar_get(obj, id);
}

#instance_variable_set(symbol, obj) ⇒ Object

Sets the instance variable names by symbol to object, thereby frustrating the efforts of the class's author to attempt to provide proper encapsulation. The variable did not have to exist prior to this call.

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\">"

Returns:



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# File 'object.c', line 2133

static VALUE
rb_obj_ivar_set(VALUE obj, VALUE iv, VALUE val)
{
    ID id = rb_to_id(iv);

    if (!rb_is_instance_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as an instance variable name",
		      QUOTE_ID(id));
    }
    return rb_ivar_set(obj, id, val);
}

#instance_variablesArray

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]

Returns:



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# File 'variable.c', line 1362

VALUE
rb_obj_instance_variables(VALUE obj)
{
    VALUE ary;

    ary = rb_ary_new();
    rb_ivar_foreach(obj, ivar_i, ary);
    return ary;
}

#is_a?Boolean #kind_of?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

Overloads:

  • #is_a?Boolean

    Returns:

    • (Boolean)
  • #kind_of?Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 581

VALUE
rb_obj_is_kind_of(VALUE obj, VALUE c)
{
    VALUE cl = CLASS_OF(obj);

    c = class_or_module_required(c);
    while (cl) {
	if (cl == c || RCLASS_M_TBL(cl) == RCLASS_M_TBL(c))
	    return Qtrue;
	cl = RCLASS_SUPER(cl);
    }
    return Qfalse;
}

#is_a?Boolean #kind_of?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

Overloads:

  • #is_a?Boolean

    Returns:

    • (Boolean)
  • #kind_of?Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 581

VALUE
rb_obj_is_kind_of(VALUE obj, VALUE c)
{
    VALUE cl = CLASS_OF(obj);

    c = class_or_module_required(c);
    while (cl) {
	if (cl == c || RCLASS_M_TBL(cl) == RCLASS_M_TBL(c))
	    return Qtrue;
	cl = RCLASS_SUPER(cl);
    }
    return Qfalse;
}

#method(sym) ⇒ Object

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"


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# File 'proc.c', line 1236

VALUE
rb_obj_method(VALUE obj, VALUE vid)
{
    ID id = rb_check_id(&vid);
    if (!id) {
	rb_method_name_error(CLASS_OF(obj), vid);
    }
    return mnew(CLASS_OF(obj), obj, id, rb_cMethod, FALSE);
}

#methods(all = 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 all parameter is set to false, only those methods in the receiver will be listed.

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   #=> 57

Returns:



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# File 'class.c', line 1128

VALUE
rb_obj_methods(int argc, VALUE *argv, VALUE obj)
{
  retry:
    if (argc == 0) {
	return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_i);
    }
    else {
	VALUE recur;

	rb_scan_args(argc, argv, "1", &recur);
	if (RTEST(recur)) {
	    argc = 0;
	    goto retry;
	}
	return rb_obj_singleton_methods(argc, argv, obj);
    }
}

#nil?Boolean

call_seq:

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

Only the object nil responds true to nil?.

Returns:

  • (Boolean)


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# File 'object.c', line 1280

static VALUE
rb_false(VALUE obj)
{
    return Qfalse;
}

#hashFixnum

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 Hash class.

Any hash value that exceeds the capacity of a Fixnum will be truncated before being used.

Returns:



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# File 'gc.c', line 1688

VALUE
rb_obj_id(VALUE obj)
{
    /*
     *                32-bit VALUE space
     *          MSB ------------------------ LSB
     *  false   00000000000000000000000000000000
     *  true    00000000000000000000000000000010
     *  nil     00000000000000000000000000000100
     *  undef   00000000000000000000000000000110
     *  symbol  ssssssssssssssssssssssss00001110
     *  object  oooooooooooooooooooooooooooooo00        = 0 (mod sizeof(RVALUE))
     *  fixnum  fffffffffffffffffffffffffffffff1
     *
     *                    object_id space
     *                                       LSB
     *  false   00000000000000000000000000000000
     *  true    00000000000000000000000000000010
     *  nil     00000000000000000000000000000100
     *  undef   00000000000000000000000000000110
     *  symbol   000SSSSSSSSSSSSSSSSSSSSSSSSSSS0        S...S % A = 4 (S...S = s...s * A + 4)
     *  object   oooooooooooooooooooooooooooooo0        o...o % A = 0
     *  fixnum  fffffffffffffffffffffffffffffff1        bignum if required
     *
     *  where A = sizeof(RVALUE)/4
     *
     *  sizeof(RVALUE) is
     *  20 if 32-bit, double is 4-byte aligned
     *  24 if 32-bit, double is 8-byte aligned
     *  40 if 64-bit
     */
    if (SYMBOL_P(obj)) {
        return (SYM2ID(obj) * sizeof(RVALUE) + (4 << 2)) | FIXNUM_FLAG;
    }
    else if (FLONUM_P(obj)) {
#if SIZEOF_LONG == SIZEOF_VOIDP
	return LONG2NUM((SIGNED_VALUE)obj);
#else
	return LL2NUM((SIGNED_VALUE)obj);
#endif
    }
    else if (SPECIAL_CONST_P(obj)) {
	return LONG2NUM((SIGNED_VALUE)obj);
    }
    return nonspecial_obj_id(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.

Returns:



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# File 'class.c', line 1171

VALUE
rb_obj_private_methods(int argc, 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.

Returns:



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# File 'class.c', line 1156

VALUE
rb_obj_protected_methods(int argc, VALUE *argv, VALUE obj)
{
    return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_prot_i);
}

#public_method(sym) ⇒ Object

Similar to method, searches public method only.



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# File 'proc.c', line 1253

VALUE
rb_obj_public_method(VALUE obj, VALUE vid)
{
    ID id = rb_check_id(&vid);
    if (!id) {
	rb_method_name_error(CLASS_OF(obj), vid);
    }
    return mnew(CLASS_OF(obj), obj, id, rb_cMethod, 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.

Returns:



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# File 'class.c', line 1186

VALUE
rb_obj_public_methods(int argc, VALUE *argv, VALUE obj)
{
    return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_pub_i);
}

#public_send(symbol[, args...]) ⇒ Object

Invokes the method identified by symbol, passing it any arguments specified. Unlike send, public_send calls public methods only.

1.public_send(:puts, "hello")  # causes NoMethodError

Returns:



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# File 'vm_eval.c', line 899

VALUE
rb_f_public_send(int argc, VALUE *argv, VALUE recv)
{
    return send_internal(argc, argv, recv, CALL_PUBLIC);
}

#rawVALUEObject

:nodoc:



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# File 'parse.y', line 11337

static VALUE
ripper_value(VALUE self, VALUE obj)
{
    return ULONG2NUM(obj);
}

#remove_instance_variable(symbol) ⇒ Object

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

Returns:



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# File 'variable.c', line 1394

VALUE
rb_obj_remove_instance_variable(VALUE obj, VALUE name)
{
    VALUE val = Qnil;
    const ID id = rb_check_id(&name);
    st_data_t n, v;
    struct st_table *iv_index_tbl;
    st_data_t index;

    if (!OBJ_UNTRUSTED(obj) && rb_safe_level() >= 4)
	rb_raise(rb_eSecurityError, "Insecure: can't modify instance variable");
    rb_check_frozen(obj);
    if (!id) {
	if (rb_is_instance_name(name)) {
	    rb_name_error_str(name, "instance variable %"PRIsVALUE" not defined",
			      name);
	}
	else {
	    rb_name_error_str(name, "`%"PRIsVALUE"' is not allowed as an instance variable name",
			      QUOTE(name));
	}
    }
    if (!rb_is_instance_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as an instance variable name",
		      QUOTE_ID(id));
    }

    if (SPECIAL_CONST_P(obj)) goto generic;
    switch (BUILTIN_TYPE(obj)) {
      case T_OBJECT:
        iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);
        if (!iv_index_tbl) break;
        if (!st_lookup(iv_index_tbl, (st_data_t)id, &index)) break;
        if (ROBJECT_NUMIV(obj) <= (long)index) break;
        val = ROBJECT_IVPTR(obj)[index];
        if (val != Qundef) {
            ROBJECT_IVPTR(obj)[index] = Qundef;
            return val;
        }
	break;
      case T_CLASS:
      case T_MODULE:
	n = id;
	if (RCLASS_IV_TBL(obj) && st_delete(RCLASS_IV_TBL(obj), &n, &v)) {
	    return (VALUE)v;
	}
	break;
      default:
      generic:
	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
	    v = val;
	    if (generic_ivar_remove(obj, (st_data_t)id, &v)) {
		return (VALUE)v;
	    }
	}
	break;
    }
    rb_name_error(id, "instance variable %"PRIsVALUE" not defined", QUOTE_ID(id));

    UNREACHABLE;
}

#respond_to?(symbol, 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.

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'vm_method.c', line 1577

static VALUE
obj_respond_to(int argc, VALUE *argv, VALUE obj)
{
    VALUE mid, priv;
    ID id;

    rb_scan_args(argc, argv, "11", &mid, &priv);
    if (!(id = rb_check_id(&mid))) {
	if (!rb_method_basic_definition_p(CLASS_OF(obj), idRespond_to_missing)) {
	    VALUE args[2];
	    args[0] = ID2SYM(rb_to_id(mid));
	    args[1] = priv;
	    return rb_funcall2(obj, idRespond_to_missing, 2, args);
	}
	return Qfalse;
    }
    if (basic_obj_respond_to(obj, id, !RTEST(priv)))
	return Qtrue;
    return Qfalse;
}

#respond_to_missing?(symbol, include_all) ⇒ Boolean

DO NOT USE THIS DIRECTLY.

Hook method to return whether the obj can respond to id method or not.

See #respond_to?.

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'vm_method.c', line 1609

static VALUE
obj_respond_to_missing(VALUE obj, VALUE mid, VALUE priv)
{
    return Qfalse;
}

#send(symbol[, args...]) ⇒ Object #__send__(symbol[, args...]) ⇒ Object

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"

Overloads:



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# File 'vm_eval.c', line 882

VALUE
rb_f_send(int argc, VALUE *argv, VALUE recv)
{
    return send_internal(argc, argv, recv, CALL_FCALL);
}

#singleton_classClass

Returns the singleton class of obj. This method creates a new singleton class if obj does not have it.

If obj is nil, true, or false, it returns NilClass, TrueClass, or FalseClass, respectively. If obj is a Fixnum or a Symbol, it raises a TypeError.

Object.new.singleton_class  #=> #<Class:#<Object:0xb7ce1e24>>
String.singleton_class      #=> #<Class:String>
nil.singleton_class         #=> NilClass

Returns:



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# File 'object.c', line 216

static VALUE
rb_obj_singleton_class(VALUE obj)
{
    return rb_singleton_class(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. 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]

Returns:



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# File 'class.c', line 1225

VALUE
rb_obj_singleton_methods(int argc, VALUE *argv, VALUE obj)
{
    VALUE recur, ary, klass;
    st_table *list;

    if (argc == 0) {
	recur = Qtrue;
    }
    else {
	rb_scan_args(argc, argv, "01", &recur);
    }
    klass = CLASS_OF(obj);
    list = st_init_numtable();
    if (klass && FL_TEST(klass, FL_SINGLETON)) {
	if (RCLASS_M_TBL(klass))
	    st_foreach(RCLASS_M_TBL(klass), method_entry_i, (st_data_t)list);
	klass = RCLASS_SUPER(klass);
    }
    if (RTEST(recur)) {
	while (klass && (FL_TEST(klass, FL_SINGLETON) || RB_TYPE_P(klass, T_ICLASS))) {
	    if (RCLASS_M_TBL(klass))
		st_foreach(RCLASS_M_TBL(klass), method_entry_i, (st_data_t)list);
	    klass = RCLASS_SUPER(klass);
	}
    }
    ary = rb_ary_new();
    st_foreach(list, ins_methods_i, ary);
    st_free_table(list);

    return ary;
}

#taintObject

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.

Returns:



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# File 'object.c', line 858

VALUE
rb_obj_taint(VALUE obj)
{
    rb_secure(4);
    if (!OBJ_TAINTED(obj)) {
	rb_check_frozen(obj);
	OBJ_TAINT(obj);
    }
    return obj;
}

#tainted?Boolean

Returns true if the object is tainted.

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 841

VALUE
rb_obj_tainted(VALUE obj)
{
    if (OBJ_TAINTED(obj))
	return Qtrue;
    return Qfalse;
}

#tap {|x| ... } ⇒ Object

Yields x to the block, and then returns x. The primary purpose of this method is to "tap into" a method chain, in order to perform operations on intermediate results within the chain.

(1..10) .tap {|x| puts "original: #{x.inspect}"}

.to_a                .tap {|x| puts "array: #{x.inspect}"}
.select {|x| x%2==0} .tap {|x| puts "evens: #{x.inspect}"}
.map { |x| x*x }     .tap {|x| puts "squares: #{x.inspect}"}

Yields:

  • (x)

Returns:



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# File 'object.c', line 611

VALUE
rb_obj_tap(VALUE obj)
{
    rb_yield(obj);
    return obj;
}

#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

Creates a new Enumerator which will enumerate by calling method on obj, passing args if any.

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)

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

Overloads:



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# File 'enumerator.c', line 240

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()) {
	enumerator_ptr(enumerator)->size = rb_block_proc();
    }
    return enumerator;
}

#to_sString

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.''

Returns:



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# File 'object.c', line 383

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);
    OBJ_INFECT(str, obj);

    return str;
}

#trustObject

Removes the untrusted mark from obj.

Returns:



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# File 'object.c', line 929

VALUE
rb_obj_trust(VALUE obj)
{
    rb_secure(3);
    if (OBJ_UNTRUSTED(obj)) {
	rb_check_frozen(obj);
	FL_UNSET(obj, FL_UNTRUSTED);
    }
    return obj;
}

#untaintObject

Removes the taint from obj.

Returns:



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# File 'object.c', line 877

VALUE
rb_obj_untaint(VALUE obj)
{
    rb_secure(3);
    if (OBJ_TAINTED(obj)) {
	rb_check_frozen(obj);
	FL_UNSET(obj, FL_TAINT);
    }
    return obj;
}

#untrustObject

Marks obj as untrusted.

Returns:



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# File 'object.c', line 910

VALUE
rb_obj_untrust(VALUE obj)
{
    rb_secure(4);
    if (!OBJ_UNTRUSTED(obj)) {
	rb_check_frozen(obj);
	OBJ_UNTRUST(obj);
    }
    return obj;
}

#untrusted?Boolean

Returns true if the object is untrusted.

Returns:

  • (Boolean)

Returns:

  • (Boolean)


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# File 'object.c', line 895

VALUE
rb_obj_untrusted(VALUE obj)
{
    if (OBJ_UNTRUSTED(obj))
	return Qtrue;
    return Qfalse;
}

#validate_objectObject

:nodoc:



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# File 'parse.y', line 10884

static VALUE
ripper_validate_object(VALUE self, VALUE x)
{
    if (x == Qfalse) return x;
    if (x == Qtrue) return x;
    if (x == Qnil) return x;
    if (x == Qundef)
        rb_raise(rb_eArgError, "Qundef given");
    if (FIXNUM_P(x)) return x;
    if (SYMBOL_P(x)) return x;
    if (!rb_is_pointer_to_heap(x))
        rb_raise(rb_eArgError, "invalid pointer: %p", x);
    switch (TYPE(x)) {
      case T_STRING:
      case T_OBJECT:
      case T_ARRAY:
      case T_BIGNUM:
      case T_FLOAT:
        return x;
      case T_NODE:
	if (nd_type(x) != NODE_LASGN) {
	    rb_raise(rb_eArgError, "NODE given: %p", x);
	}
	return ((NODE *)x)->nd_rval;
      default:
        rb_raise(rb_eArgError, "wrong type of ruby object: %p (%s)",
                 x, rb_obj_classname(x));
    }
    return x;
}