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<dl>
<dt> <H1>Object</H1>
<dd>
<P>
The super class of all the Ruby class hierarchy.
</P>
<dt> <h2>SuperClass:</h2>
<dd>
<dl>
<dt> <A HREF="Kernel.html"><code>Kernel</code></A>
</dl>
<dt> <h2>Methods:</h2>
<dd>
<DL COMPACT>
<DT>
<A NAME="eq">
<CODE>self == <VAR>other</VAR></CODE></A>
<DD>
<p>
Checks if two objects are <strong>equal</strong>. The default
definition in the <code>Kernel</code> class checks by object ID. It
should be redefined in subclasses according to the characteristic of
the class.
</p>
<DT>
<A NAME="clone"><CODE>clone</CODE></A>
<DD>
<DT><A NAME="dup"><CODE>dup</CODE></A>
<DD>
<p>
Returns the copy of the object. For cloned object,
<blockquote>
<pre>
obj == obj.clone
</pre>
</blockquote>
<code></code>
is always true, though
<blockquote>
<pre>
obj.equal?(obj.clone)
</pre>
</blockquote>
<code></code>
is false most of the time.
</p>
<p>
the <code>dup</code> method is defined as:
<blockquote>
<pre>
def dup
self.clone
end
</pre>
</blockquote>
</p>
<p>
<code>clone</code> and <code>dup</code> copy the receiver, but they do
not copy the objects pointed by the receiver (i.e shallow copy).
</p>
<DT>
<A NAME="display"><CODE>display([<VAR>port</VAR>])</CODE></A>
<DD>
<p>
Prints <code>self</code> to the <var>port</var>. The <var>port</var>'s
default value is <code>$></code>.
</p>
<blockquote>
<pre>
def display(out=$>)
out.print self
end
public :display
</pre>
</blockquote>
<DT>
<A NAME="eql_p">
<CODE>eql?(<VAR>other</VAR>)</CODE></A>
<DD>
<p>
Checks if two objects are <strong>equal</strong>. This method is used
by <a href="Hash.html"><code>Hash</code></a> to compare whether two
keys are same. When this method is redefined, the <code>hash</code>
method should be updated.
</p>
<p>
The default definition of the method <code>eql?</code> is
like blow:
</p>
<p>
<blockquote>
<pre>
def eql?(other)
self == other
end
</pre>
</blockquote>
</p>
<DT>
<A NAME="equal_p">
<CODE>equal?(<VAR>other</VAR>)</CODE></A>
<DD>
<p>
Checks if two objects have same object ID. This method
should not be redefined in the subclass.
</p>
<DT>
<A NAME="match"><CODE>self =~ <VAR>other</VAR></CODE></A>
<DD>
<p>
Method for old style match like <code>obj =~ /RE/</code>.
The default definitions is `<code><a href="#equal">==</a></code>'.
</p>
<DT>
<A NAME="eqq">
<CODE>self === <VAR>other</VAR></CODE></A>
<DD>
<p>
This method is used to compare in <code><a href="syntax.html#case">case</a></code>.
The default definitions is `<code><a href="#equal">==</a></code>'.
</p>
<DT>
<A NAME="extend">
<CODE>extend(module...)</CODE></A>
<DD>
<p>
Extends <code>self</code> by adding methods defined in
<var>module</var>s as singleton-methods.
</p>
<DT>
<A NAME="hash">
<CODE>hash</CODE></A>
<DD>
<p>
Returns the integer hash value of the object. It is used in the
<code><a href="Hash.html">Hash</a></code> class to calculate the
holding place of an object. The hash value of two objects must be
equal, where these two objects are equal by using <code>eql?</code>
operator. So, whenever you redefine the definition of the
<code>eql?</code> operator in any class, don't forget to redefine
<code>hash</code> method according to the definition.
</p>
<DT>
<A NAME="id">
<CODE>id</CODE></A>
<DD>
<p>
Returns the unique integer value for each object.
</p>
<DT>
<A NAME="inspect">
<CODE>inspect</CODE></A>
<DD>
<p>
Returns the human-readable string representation of the receiver.
</p>
<DT>
<A NAME="initialize">
<CODE>initialize(...)</CODE></A>
<DD>
<p>
The initialize method for the user-defined classes. This method will
be called from <code><a href="Class.html#new">Class#new</a></code> to
initialize the newly created object.
The default behavior is to do nothing. It is assumed that this method
will be redefined in the subclasses. The argument to
<code><a href="Class.html#new">Class#new</a></code> will be passed to
the <code>initialize</code>
</p>
<p>
the method named <code>initialize</code> automatically falls under
private visibility.
</p>
<DT>
<A NAME="instance_eval"><CODE>instance_eval(<VAR>expr</VAR>)</CODE></A>
<DD>
<DT>
<CODE>instance_eval{...}</CODE>
<DD>
<p>
Evaluates the <var>expr</var> string in the object context. If block
supplied for the method, the block is evaluated under the receiver's
context. This allows to avoid compiling the string everytime.
</p>
<p>
In <var>instance_eval</var>'s context, <code>self</code> is bound to
the object, so that instance variables and methods of the receiver are
accessed.
</p>
<DT>
<A NAME="instance_of_p">
<CODE>instance_of?(<VAR>class</VAR>)</CODE></A>
<DD>
<p>
Returns true, if <code>self</code> is an instance of the specified
<var>class</var>. It is always true, when
<CODE><a href="#kind_of_p">obj.kind_of?(c)</a></CODE> is true.
</p>
<DT>
<A NAME="instance_variables"><CODE>instance_variables()</CODE></A>
<DD>
<p>
Returns the array of <code>self</code>'s instance variable names.
</p>
<DT>
<A NAME="kind_of_p">
<CODE>kind_of?(<VAR>class</VAR>)</CODE></A>
<DD>
<dt>
<A NAME="is_a_p">
<code>is_a?(<VAR>class</VAR>)</code></A>
<dd>
<p>
Returns true, if <code>self</code> is an instance of the specified
<var>class</var>, or its subclass.
</p>
<DT>
<A NAME="method_missing">
<CODE>method_missing(<var>msg_id</var>, ...)</CODE></A>
<DD>
<p>
Will be called when the specified method is not defined for the
receiver. The first argument, <var>msg_id</var> is the method name as
a symbol. The second and later arguments are the arguments given to
the undefined method, if any.
</p>
<dt> <a name="methods"><code>methods</code></a>
<dd>
<p>
Returns the array of the public method names which defined in the receiver.
</p>
<DT>
<A NAME="nil_p">
<CODE>nil?</CODE></A>
<DD>
<p>
Checks whether the receiver is <code>nil</code> or not.
</p>
<dt> <a name="private_methods"><code>private_methods</code></a>
<dd>
<p>
Returns the array of the private method names which defined in the
receiver.
</p>
<dt> <a name="remove_instance_variable"><code>remove_instance_variable(<var>name</var>)</code></a>
<dd>
<p>
Removes specified instance variable from the object. It does not
raise any exception even if the object does not have named instance
variable.
</p>
<dt> <a name="respond_to_p">
<code>respond_to?(<var>mesg</var>[,<var>priv</var>])</code></a>
<dd>
<p>
Returns true if the receiver has the public method named
<var>mesg</var>. <var>Mesg</var> must be the symbol fixnum or the
string. It returns true for private methods, if the optional argument
<var>priv</var> given, and its value is true,
</p>
<DT><A NAME="send">
<CODE>send(<VAR>symbol</VAR>[, <VAR>args</VAR>...])</CODE></A>
<DD>
<p>
calls the method specified by the <var>symbol</var>, with
<var>args</var>.
</p>
<DT><A NAME="singleton_method_added"><CODE>singleton_method_added(<var>id</var>)</CODE></A>
<DD>
<p>
Will be called when the singleton method defined for the receiver.
</p>
<dt> <a name="singleton_methods"><code>singleton_methods</code></a>
<dd>
<p>
Returns the array of the singleton method names which defined in the receiver.
</p>
<DT><A NAME="taint"><CODE>taint</CODE></A>
<DD>
<p>
Turns on `taint mark' of the object.
</p>
<DT><A NAME="tainted_p"><CODE>tainted?</CODE></A>
<DD>
<p>
Returns true if the string is `tainted'.
</p>
<DT>
<A NAME="to_s">
<CODE>to_s</CODE></A>
<DD>
<p>
Returns the string representation of the <code>self</code>.
This method is used internally by
<code><a href="function.html#print">print</a></code> and
<code><a href="function.html#sprintf">sprintf</a></code>.
</p>
<DT>
<A NAME="to_a">
<CODE>to_a</CODE></A>
<DD>
<p>
Converts the <code>self</code> into an array. Returns an array of 1
element contains <code>self</code> for classes would not be converted
into an array naturally.
</p>
<DT><A NAME="type">
<CODE>type</CODE></A>
<DD>
<p>
Returns the receiver's class.
</p>
<DT><A NAME="untaint"><CODE>untaint</CODE></A>
<DD>
<p>
Turns off `taint mark' of the object. Programmers should be responsible
for the security issue caused by removing the taint mark. The mark
can't be removed if the security level ($SAFE) is greater than or equals
to level 3.
</p>
</DL>
</dl>
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