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In Files

  • class.c
  • object.c
  • vm_eval.c

BasicObject

BasicObject is the parent class of all classes in Ruby. It's an explicit blank class.

Public Class Methods

new(*args) click to toggle source

Not documented

 
               static VALUE
rb_obj_dummy(void)
{
    return Qnil;
}
            

Public Instance Methods

!obj → true or false click to toggle source

Boolean negate.

 
               VALUE
rb_obj_not(VALUE obj)
{
    return RTEST(obj) ? Qfalse : Qtrue;
}
            
obj != other → true or false click to toggle source

Returns true if two objects are not-equal, otherwise false.

 
               VALUE
rb_obj_not_equal(VALUE obj1, VALUE obj2)
{
    VALUE result = rb_funcall(obj1, id_eq, 1, obj2);
    return RTEST(result) ? Qfalse : Qtrue;
}
            
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 descendant 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
 
               VALUE
rb_obj_equal(VALUE obj1, VALUE obj2)
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}
            
send(symbol [, args...]) → obj click to toggle source
__send__(symbol [, args...]) → obj

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

class Klass
  def hello(*args)
    "Hello " + args.join(' ')
  end
end
k = Klass.new
k.send :hello, "gentle", "readers"   #=> "Hello gentle readers"
 
               VALUE
rb_f_send(int argc, VALUE *argv, VALUE recv)
{
    return send_internal(argc, argv, recv, CALL_FCALL);
}
            
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 descendant 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
 
               VALUE
rb_obj_equal(VALUE obj1, VALUE obj2)
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}
            
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 KlassWithSecret
  def initialize
    @secret = 99
  end
end
k = KlassWithSecret.new
k.instance_eval { @secret }   #=> 99
 
               VALUE
rb_obj_instance_eval(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(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));
}
            

Private Instance Methods

method_missing(symbol [, *args] ) → result click to toggle source

Invoked by Ruby when obj is sent a message it cannot handle. symbol is the symbol for the method called, and args are any arguments that were passed to it. By default, the interpreter raises an error when this method is called. However, it is possible to override the method to provide more dynamic behavior. If it is decided that a particular method should not be handled, then super should be called, so that ancestors can pick up the missing method. The example below creates a class Roman, which responds to methods with names consisting of roman numerals, returning the corresponding integer values.

class Roman
  def romanToInt(str)
    # ...
  end
  def method_missing(methId)
    str = methId.id2name
    romanToInt(str)
  end
end

r = Roman.new
r.iv      #=> 4
r.xxiii   #=> 23
r.mm      #=> 2000
 
               static VALUE
rb_method_missing(int argc, const VALUE *argv, VALUE obj)
{
    rb_thread_t *th = GET_THREAD();
    raise_method_missing(th, argc, argv, obj, th->method_missing_reason);
    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(void)
{
    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(void)
{
    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(void)
{
    return Qnil;
}
            

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