In Files

  • enumerator.c
  • eval.c
  • gc.c
  • hash.c
  • io.c
  • object.c
  • re.c
  • ruby.c
  • version.c

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).

Public Class Methods

new() click to toggle source

Not documented

 
               static VALUE
rb_obj_dummy()
{
    return Qnil;
}
            

Public Instance Methods

obj == other => true or false click to toggle source

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
 
               static VALUE
rb_obj_equal(obj1, obj2)
    VALUE obj1, obj2;
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}
            
obj === other => true or false click to toggle source

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

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

    if (obj1 == obj2) return Qtrue;
    result = rb_funcall(obj1, id_eq, 1, obj2);
    if (RTEST(result)) return Qtrue;
    return Qfalse;
}
            
obj =~ other => false click to toggle source

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

 
               static VALUE
rb_obj_pattern_match(obj1, obj2)
    VALUE obj1, obj2;
{
    return Qfalse;
}
            
__id__ => fixnum click to toggle source

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.

 
               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 (TYPE(obj) == T_SYMBOL) {
        return (SYM2ID(obj) * sizeof(RVALUE) + (4 << 2)) | FIXNUM_FLAG;
    }
    if (SPECIAL_CONST_P(obj)) {
        return LONG2NUM((long)obj);
    }
    return (VALUE)((long)obj|FIXNUM_FLAG);
}
            
__send__(symbol [, args...]) => obj click to toggle source

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"
 
               static VALUE
rb_f_send(argc, argv, recv)
    int argc;
    VALUE *argv;
    VALUE recv;
{
    VALUE vid;

    if (argc == 0) rb_raise(rb_eArgError, "no method name given");

    vid = *argv++; argc--;
    PUSH_ITER(rb_block_given_p()?ITER_PRE:ITER_NOT);
    vid = rb_call(CLASS_OF(recv), recv, rb_to_id(vid), argc, argv, 1, Qundef);
    POP_ITER();

    return vid;
}
            
class => class click to toggle source

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
 
               VALUE
rb_obj_class(obj)
    VALUE obj;
{
    return rb_class_real(CLASS_OF(obj));
}
            
clone → an_object click to toggle source

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.

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

    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));
    RBASIC(clone)->klass = rb_singleton_class_clone(obj);
    RBASIC(clone)->flags = (RBASIC(obj)->flags | FL_TEST(clone, FL_TAINT)) & ~(FL_FREEZE|FL_FINALIZE);
    init_copy(clone, obj);
    RBASIC(clone)->flags |= RBASIC(obj)->flags & FL_FREEZE;

    return clone;
}
            
display(port=$>) => nil click to toggle source

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

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

    rb_io_write(out, self);

    return Qnil;
}
            
dup → an_object click to toggle source

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.

 
               VALUE
rb_obj_dup(obj)
    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);

    return dup;
}
            
enum_for(method = :each, *args) click to toggle source

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)
 
               static VALUE
obj_to_enum(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE meth = sym_each;

    if (argc > 0) {
        --argc;
        meth = *argv++;
    }
    return rb_enumeratorize(obj, meth, argc, argv);
}
            
eql?(other) => true or false click to toggle source

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
 
               static VALUE
rb_obj_equal(obj1, obj2)
    VALUE obj1, obj2;
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}
            
equal?(other) => true or false click to toggle source

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
 
               static VALUE
rb_obj_equal(obj1, obj2)
    VALUE obj1, obj2;
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}
            
extend(module, ...) => obj click to toggle source

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"
 
               static VALUE
rb_obj_extend(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    int i;

    if (argc == 0) {
        rb_raise(rb_eArgError, "wrong number of arguments (0 for 1)");
    }
    for (i=0; i<argc; i++) Check_Type(argv[i], T_MODULE);
    while (argc--) {
        rb_funcall(argv[argc], rb_intern("extend_object"), 1, obj);
        rb_funcall(argv[argc], rb_intern("extended"), 1, obj);
    }
    return obj;
}
            
freeze => obj click to toggle source

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
 
               VALUE
rb_obj_freeze(obj)
    VALUE obj;
{
    if (!OBJ_FROZEN(obj)) {
        if (rb_safe_level() >= 4 && !OBJ_TAINTED(obj)) {
            rb_raise(rb_eSecurityError, "Insecure: can't freeze object");
        }
        OBJ_FREEZE(obj);
    }
    return obj;
}
            
frozen? => true or false click to toggle source

Returns the freeze status of obj.

a = [ "a", "b", "c" ]
a.freeze    #=> ["a", "b", "c"]
a.frozen?   #=> true
 
               static VALUE
rb_obj_frozen_p(obj)
    VALUE obj;
{
    if (OBJ_FROZEN(obj)) return Qtrue;
    return Qfalse;
}
            
hash => fixnum click to toggle source

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.

 
               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 (TYPE(obj) == T_SYMBOL) {
        return (SYM2ID(obj) * sizeof(RVALUE) + (4 << 2)) | FIXNUM_FLAG;
    }
    if (SPECIAL_CONST_P(obj)) {
        return LONG2NUM((long)obj);
    }
    return (VALUE)((long)obj|FIXNUM_FLAG);
}
            
id => fixnum click to toggle source

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

 
               VALUE
rb_obj_id_obsolete(obj)
    VALUE obj;
{
    rb_warn("Object#id will be deprecated; use Object#object_id");
    return rb_obj_id(obj);
}
            
inspect => string click to toggle source

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"
 
               static VALUE
rb_obj_inspect(obj)
    VALUE obj;
{
    if (TYPE(obj) == T_OBJECT
        && ROBJECT(obj)->iv_tbl
        && ROBJECT(obj)->iv_tbl->num_entries > 0) {
        VALUE str;
        size_t len;
        const char *c = rb_obj_classname(obj);

        if (rb_inspecting_p(obj)) {
            len = strlen(c)+10+16+1;
            str = rb_str_new(0, len); /* 10:tags 16:addr 1:nul */
            snprintf(RSTRING(str)->ptr, len, "#<%s:0x%lx ...>", c, obj);
            RSTRING(str)->len = strlen(RSTRING(str)->ptr);
            return str;
        }
        len = strlen(c)+6+16+1;
        str = rb_str_new(0, len);     /* 6:tags 16:addr 1:nul */
        snprintf(RSTRING(str)->ptr, len, "-<%s:0x%lx", c, obj);
        RSTRING(str)->len = strlen(RSTRING(str)->ptr);
        return rb_protect_inspect(inspect_obj, obj, str);
    }
    return rb_funcall(obj, rb_intern("to_s"), 0, 0);
}
            
instance_eval(string [, filename [, lineno]] ) => obj click to toggle source
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
 
               VALUE
rb_obj_instance_eval(argc, argv, self)
    int argc;
    VALUE *argv;
    VALUE self;
{
    VALUE klass;

    if (SPECIAL_CONST_P(self)) {
        klass = Qnil;
    }
    else {
        klass = rb_singleton_class(self);
    }
    return specific_eval(argc, argv, klass, self);
}
            
instance_exec(arg...) {|var...| block } => obj click to toggle source

Executes 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. Arguments are passed as block parameters.

class KlassWithSecret
  def initialize
    @secret = 99
  end
end
k = KlassWithSecret.new
k.instance_exec(5) {|x| @secret+x }   #=> 104
 
               VALUE
rb_obj_instance_exec(argc, argv, self)
    int argc;
    VALUE *argv;
    VALUE self;
{
    VALUE klass;

    if (SPECIAL_CONST_P(self)) {
        klass = Qnil;
    }
    else {
        klass = rb_singleton_class(self);
    }
    return yield_under(klass, self, rb_ary_new4(argc, argv));
}
            
instance_of?(class) => true or false click to toggle source

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

 
               VALUE
rb_obj_is_instance_of(obj, c)
    VALUE obj, c;
{
    switch (TYPE(c)) {
      case T_MODULE:
      case T_CLASS:
      case T_ICLASS:
        break;
      default:
        rb_raise(rb_eTypeError, "class or module required");
    }

    if (rb_obj_class(obj) == c) return Qtrue;
    return Qfalse;
}
            
instance_variable_defined?(symbol) => true or false click to toggle source

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

    if (!rb_is_instance_id(id)) {
        rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
    }
    return rb_ivar_defined(obj, id);
}
            
instance_variable_get(symbol) => obj click to toggle source

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

    if (!rb_is_instance_id(id)) {
        rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
    }
    return rb_ivar_get(obj, id);
}
            
instance_variable_set(symbol, obj) => obj click to toggle source

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

    if (!rb_is_instance_id(id)) {
        rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
    }
    return rb_ivar_set(obj, id, val);
}
            
instance_variables => array click to toggle source

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"]
 
               VALUE
rb_obj_instance_variables(obj)
    VALUE obj;
{
    VALUE ary;

    ary = rb_ary_new();
    switch (TYPE(obj)) {
      case T_OBJECT:
      case T_CLASS:
      case T_MODULE:
	if (ROBJECT(obj)->iv_tbl) {
	    st_foreach_safe(ROBJECT(obj)->iv_tbl, ivar_i, ary);
	}
	break;
      default:
	if (!generic_iv_tbl) break;
	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
	    st_data_t tbl;

	    if (st_lookup(generic_iv_tbl, obj, &tbl)) {
		st_foreach_safe((st_table *)tbl, ivar_i, ary);
	    }
	}
	break;
    }
    return ary;
}
            
is_a?(class) => true or false click to toggle source

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

    switch (TYPE(c)) {
      case T_MODULE:
      case T_CLASS:
      case T_ICLASS:
        break;

      default:
        rb_raise(rb_eTypeError, "class or module required");
    }

    while (cl) {
        if (cl == c || RCLASS(cl)->m_tbl == RCLASS(c)->m_tbl)
            return Qtrue;
        cl = RCLASS(cl)->super;
    }
    return Qfalse;
}
            
kind_of?(class) => true or false click to toggle source

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

    switch (TYPE(c)) {
      case T_MODULE:
      case T_CLASS:
      case T_ICLASS:
        break;

      default:
        rb_raise(rb_eTypeError, "class or module required");
    }

    while (cl) {
        if (cl == c || RCLASS(cl)->m_tbl == RCLASS(c)->m_tbl)
            return Qtrue;
        cl = RCLASS(cl)->super;
    }
    return Qfalse;
}
            
method(sym) => method click to toggle source

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"
 
               VALUE
rb_obj_method(obj, vid)
    VALUE obj;
    VALUE vid;
{
    return mnew(CLASS_OF(obj), obj, rb_to_id(vid), rb_cMethod);
}
            
methods => array click to toggle source

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
 
               static VALUE
rb_obj_methods(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
  retry:
    if (argc == 0) {
        VALUE args[1];

        args[0] = Qtrue;
        return rb_class_instance_methods(1, args, CLASS_OF(obj));
    }
    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?() click to toggle source

call_seq:

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

Only the object nil responds true to nil?.

 
               static VALUE
rb_false(obj)
    VALUE obj;
{
    return Qfalse;
}
            
object_id => fixnum click to toggle source

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.

 
               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 (TYPE(obj) == T_SYMBOL) {
        return (SYM2ID(obj) * sizeof(RVALUE) + (4 << 2)) | FIXNUM_FLAG;
    }
    if (SPECIAL_CONST_P(obj)) {
        return LONG2NUM((long)obj);
    }
    return (VALUE)((long)obj|FIXNUM_FLAG);
}
            
private_methods(all=true) => array click to toggle source

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.

 
               static VALUE
rb_obj_private_methods(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    if (argc == 0) {            /* hack to stop warning */
        VALUE args[1];

        args[0] = Qtrue;
        return rb_class_private_instance_methods(1, args, CLASS_OF(obj));
    }
    return rb_class_private_instance_methods(argc, argv, CLASS_OF(obj));
}
            
protected_methods(all=true) => array click to toggle source

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.

 
               static VALUE
rb_obj_protected_methods(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    if (argc == 0) {            /* hack to stop warning */
        VALUE args[1];

        args[0] = Qtrue;
        return rb_class_protected_instance_methods(1, args, CLASS_OF(obj));
    }
    return rb_class_protected_instance_methods(argc, argv, CLASS_OF(obj));
}
            
public_methods(all=true) => array click to toggle source

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.

 
               static VALUE
rb_obj_public_methods(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    if (argc == 0) {            /* hack to stop warning */
        VALUE args[1];

        args[0] = Qtrue;
        return rb_class_public_instance_methods(1, args, CLASS_OF(obj));
    }
    return rb_class_public_instance_methods(argc, argv, CLASS_OF(obj));
}
            
respond_to?(symbol, include_private=false) => true or false click to toggle source

Returns true> if obj responds to the given method. Private methods are included in the search only if the optional second parameter evaluates to true.

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

    rb_scan_args(argc, argv, "11", &mid, &priv);
    id = rb_to_id(mid);
    if (rb_method_boundp(CLASS_OF(obj), id, !RTEST(priv))) {
        return Qtrue;
    }
    return Qfalse;
}
            
send(symbol [, args...]) => obj click to toggle source

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"
 
               static VALUE
rb_f_send(argc, argv, recv)
    int argc;
    VALUE *argv;
    VALUE recv;
{
    VALUE vid;

    if (argc == 0) rb_raise(rb_eArgError, "no method name given");

    vid = *argv++; argc--;
    PUSH_ITER(rb_block_given_p()?ITER_PRE:ITER_NOT);
    vid = rb_call(CLASS_OF(recv), recv, rb_to_id(vid), argc, argv, 1, Qundef);
    POP_ITER();

    return vid;
}
            
singleton_methods(all=true) => array click to toggle source

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

    rb_scan_args(argc, argv, "01", &recur);
    if (argc == 0) {
	recur = Qtrue;
    }
    klass = CLASS_OF(obj);
    list = st_init_numtable();
    if (klass && FL_TEST(klass, FL_SINGLETON)) {
	st_foreach(RCLASS(klass)->m_tbl, method_entry, (st_data_t)list);
	klass = RCLASS(klass)->super;
    }
    if (RTEST(recur)) {
	while (klass && (FL_TEST(klass, FL_SINGLETON) || TYPE(klass) == T_ICLASS)) {
	    st_foreach(RCLASS(klass)->m_tbl, method_entry, (st_data_t)list);
	    klass = RCLASS(klass)->super;
	}
    }
    ary = rb_ary_new();
    st_foreach(list, ins_methods_i, ary);
    st_free_table(list);

    return ary;
}
            
taint → obj click to toggle source

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.

 
               VALUE
rb_obj_taint(obj)
    VALUE obj;
{
    rb_secure(4);
    if (!OBJ_TAINTED(obj)) {
        if (OBJ_FROZEN(obj)) {
            rb_error_frozen("object");
        }
        OBJ_TAINT(obj);
    }
    return obj;
}
            
tainted? => true or false click to toggle source

Returns true if the object is tainted.

 
               VALUE
rb_obj_tainted(obj)
    VALUE obj;
{
    if (OBJ_TAINTED(obj))
        return Qtrue;
    return Qfalse;
}
            
tap{|x|...} => obj click to toggle source

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}"
}
 
               VALUE
rb_obj_tap(obj)
    VALUE obj;
{
    rb_yield(obj);
    return obj;
}
            
to_a → anArray click to toggle source

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"]
 
               static VALUE
rb_any_to_a(obj)
    VALUE obj;
{
    rb_warn("default `to_a' will be obsolete");
    return rb_ary_new3(1, obj);
}
            
to_enum(method = :each, *args) click to toggle source

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)
 
               static VALUE
obj_to_enum(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE meth = sym_each;

    if (argc > 0) {
        --argc;
        meth = *argv++;
    }
    return rb_enumeratorize(obj, meth, argc, argv);
}
            
to_s => string click to toggle source

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.”

 
               VALUE
rb_any_to_s(obj)
    VALUE obj;
{
    const char *cname = rb_obj_classname(obj);
    size_t len;
    VALUE str;

    len = strlen(cname)+6+16;
    str = rb_str_new(0, len); /* 6:tags 16:addr */
    snprintf(RSTRING(str)->ptr, len+1, "#<%s:0x%lx>", cname, obj);
    RSTRING(str)->len = strlen(RSTRING(str)->ptr);
    if (OBJ_TAINTED(obj)) OBJ_TAINT(str);

    return str;
}
            
type => class click to toggle source

Deprecated synonym for Object#class.

 
               VALUE
rb_obj_type(obj)
    VALUE obj;
{
    rb_warn("Object#type is deprecated; use Object#class");
    return rb_class_real(CLASS_OF(obj));
}
            
untaint => obj click to toggle source

Removes the taint from obj.

 
               VALUE
rb_obj_untaint(obj)
    VALUE obj;
{
    rb_secure(3);
    if (OBJ_TAINTED(obj)) {
        if (OBJ_FROZEN(obj)) {
            rb_error_frozen("object");
        }
        FL_UNSET(obj, FL_TAINT);
    }
    return obj;
}
            

Private Instance Methods

remove_instance_variable(symbol) => obj click to toggle source

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
 
               VALUE
rb_obj_remove_instance_variable(obj, name)
    VALUE obj, name;
{
    VALUE val = Qnil;
    ID id = rb_to_id(name);

    if (!OBJ_TAINTED(obj) && rb_safe_level() >= 4)
	rb_raise(rb_eSecurityError, "Insecure: can't modify instance variable");
    if (OBJ_FROZEN(obj)) rb_error_frozen("object");
    if (!rb_is_instance_id(id)) {
	rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
    }

    switch (TYPE(obj)) {
      case T_OBJECT:
      case T_CLASS:
      case T_MODULE:
	if (ROBJECT(obj)->iv_tbl && st_delete(ROBJECT(obj)->iv_tbl, (st_data_t*)&id, &val)) {
	    return val;
	}
	break;
      default:
	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
	    if (generic_ivar_remove(obj, id, &val)) {
		return val;
	    }
	}
	break;
    }
    rb_name_error(id, "instance variable %s not defined", rb_id2name(id));
    return Qnil;		/* not reached */
}
            
singleton_method_added(symbol) click to toggle source

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
 
               static VALUE
rb_obj_dummy()
{
    return Qnil;
}
            
singleton_method_removed(symbol) click to toggle source

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
 
               static VALUE
rb_obj_dummy()
{
    return Qnil;
}
            
singleton_method_undefined(symbol) click to toggle source

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
 
               static VALUE
rb_obj_dummy()
{
    return Qnil;
}
            

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