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<span id="Object_002dOriented-Methods"></span><div class="header">
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<span id="Object_002dOriented-Methods-1"></span><h4 class="subsubsection">14.5.6.2 Object-Oriented Methods</h4>
<span id="index-Methods_002c-object_002doriented"></span>
<p>These commands allow you to define different sorts of function-like
entities resembling methods in object-oriented programming languages.
These entities take arguments, as functions do, but are associated with
particular classes of objects.
</p>
<dl compact="compact">
<dd>
<span id="index-defop"></span>
</dd>
<dt><code>@defop <var>category</var> <var>class</var> <var>name</var> <var>arguments</var>…</code></dt>
<dd><p>The <code>@defop</code> command is the general definition command for these
method-like entities.
</p>
<p>For example, some systems have constructs called <em>wrappers</em> that
are associated with classes as methods are, but that act more like
macros than like functions. You could use <code>@defop Wrapper</code> to
describe one of these.
</p>
<p>Sometimes it is useful to distinguish methods and <em>operations</em>.
You can think of an operation as the specification for a method.
Thus, a window system might specify that all window classes have a
method named <code>expose</code>; we would say that this window system
defines an <code>expose</code> operation on windows in general. Typically,
the operation has a name and also specifies the pattern of arguments;
all methods that implement the operation must accept the same
arguments, since applications that use the operation do so without
knowing which method will implement it.
</p>
<p>Often it makes more sense to document operations than methods. For
example, window application developers need to know about the
<code>expose</code> operation, but need not be concerned with whether a
given class of windows has its own method to implement this operation.
To describe this operation, you would write:
</p>
<div class="example">
<pre class="example">@defop Operation windows expose
</pre></div>
<p>The <code>@defop</code> command is written at the beginning of a line and
is followed on the same line by the overall name of the category of
operation, the name of the class of the operation, the name of the
operation, and its arguments, if any.
</p>
<p>The template is:
</p><div class="example">
<pre class="example">@defop <var>category</var> <var>class</var> <var>name</var> <var>arguments</var>…
<var>body-of-definition</var>
@end defop
</pre></div>
<p><code>@defop</code> creates an entry, such as ‘<code>expose</code> on
<code>windows</code>’, in the index of functions.
</p>
<span id="index-deftypeop"></span>
</dd>
<dt><code>@deftypeop <var>category</var> <var>class</var> <var>data-type</var> <var>name</var> <var>arguments</var>…</code></dt>
<dd><p>The <code>@deftypeop</code> command is the definition command for typed
operations in object-oriented programming. It is similar to
<code>@defop</code> with the addition of the <var>data-type</var> parameter to
specify the return type of the method. <code>@deftypeop</code> creates an
entry in the index of functions.
</p>
</dd>
<dt><code>@defmethod <var>class</var> <var>name</var> <var>arguments</var>…</code></dt>
<dd><span id="index-defmethod"></span>
<p>The <code>@defmethod</code> command is the definition command for methods
in object-oriented programming. A method is a kind of function that
implements an operation for a particular class of objects and its
subclasses.
</p>
<p><code>@defmethod</code> is equivalent to ‘<samp>@defop Method …</samp>’.
The command is written at the beginning of a line and is followed by
the name of the class of the method, the name of the method, and its
arguments, if any.
</p>
<p>For example:
</p><div class="example">
<pre class="example">@defmethod <code>bar-class</code> bar-method argument
…
@end defmethod
</pre></div>
<p>illustrates the definition for a method called <code>bar-method</code> of
the class <code>bar-class</code>. The method takes an argument.
</p>
<p><code>@defmethod</code> creates an entry in the index of functions.
</p>
</dd>
<dt><code>@deftypemethod <var>class</var> <var>data-type</var> <var>name</var> <var>arguments</var>…</code></dt>
<dd><span id="index-deftypemethod"></span>
<p>The <code>@deftypemethod</code> command is the definition command for methods
in object-oriented typed languages, such as C++ and Java. It is similar
to the <code>@defmethod</code> command with the addition of the
<var>data-type</var> parameter to specify the return type of the method.
<code>@deftypemethod</code> creates an entry in the index of functions.
</p>
</dd>
</dl>
<p>The typed commands are affected by the <code>@deftypefnnewline</code>
option (see <a href="Typed-Functions.html">Functions in Typed Languages</a>).
</p>
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