Add ext/operator documentation

Author: jb-lopez

appendices/extensions.xml

@@ -94,6 +94,7 @@
    <listitem><simpara><xref linkend="book.opcache"/></simpara></listitem>
    <listitem><simpara><xref linkend="book.openal"/></simpara></listitem>
    <listitem><simpara><xref linkend="book.openssl"/></simpara></listitem>
+   <listitem><simpara><xref linkend="book.operator"/></simpara></listitem>
    <listitem><simpara><xref linkend="book.outcontrol"/></simpara></listitem>
    <listitem><simpara><xref linkend="book.parallel"/></simpara></listitem>
    <listitem><simpara><xref linkend="book.parle"/></simpara></listitem>
@@ -350,6 +351,7 @@
     <listitem><para><xref linkend="book.oauth"/></para></listitem>
     <listitem><para><xref linkend="book.oci8"/></para></listitem>
     <listitem><para><xref linkend="book.openal"/></para></listitem>
+    <listitem><para><xref linkend="book.operator"/></para></listitem>
     <listitem><para><xref linkend="book.parallel"/></para></listitem>
     <listitem><para><xref linkend="book.parle"/></para></listitem>
     <listitem><para><xref linkend="ref.pdo-cubrid"/></para></listitem>

language/operators.xml

@@ -29,6 +29,11 @@
   exactly how expressions containing several different operators are
   evaluated.
  </para>
+ <para>
+  There is a PECL extension that allows for overloading of some operators for
+  objects. For more information, see the <link linkend="book.operator">Operator
+  Overloading for Objects</link> section.
+ </para>
 
  &language.operators.precedence;
  &language.operators.arithmetic;

reference/operator/book.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- $Revision$ -->
+<book xml:id="book.operator" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
+ <?phpdoc extension-membership="pecl" ?>
+ <title>Operator Overloading for Objects</title>
+ <titleabbrev>Operator Overloading</titleabbrev>
+
+ <!-- {{{ preface -->
+ <preface xml:id="intro.operator">
+  &reftitle.intro;
+  <para>
+   This extension allows you to define and implement operator overloading for objects.
+   It is possible to define how an object reacts when an operator is used on it.
+  </para>
+  <para>
+   One example of this is creating a collection type object that has the addition
+   operator overloaded to allow adding elements to the collection or adding two
+   collections together.
+  </para>
+  <para>
+   Another example is creating an enhanced string class that has the multiplication
+   operator overloaded to allow repeating the string a certain number of times.
+  </para>
+
+  <section>
+   &reftitle.seealso;
+
+  </section>
+ </preface>
+ <!-- }}} -->
+ &reference.operator.setup;
+ &reference.operator.overloading;
+</book>