From 7ca2d3f9e4d584d8990e4e33eb3b531a06dc2474 Mon Sep 17 00:00:00 2001
From: Emiel Bruijntjes <emiel.bruijntjes@copernica.com>
Date: Sun, 6 Apr 2014 10:44:15 +0200
Subject: added documentation of the implementation() method

---
 documentation/variables.html | 81 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

(limited to 'documentation')

diff --git a/documentation/variables.html b/documentation/variables.html
index 719d95e..98a6d49 100644
--- a/documentation/variables.html
+++ b/documentation/variables.html
@@ -366,6 +366,87 @@ Php::Value value = Php::Object("DateTime", "now");
 Php::out &lt;&lt; value.call("format", "Y-m-d H:i:s") &lt;&lt; std::endl;
 </code></pre>
 </p>
+<p>
+    When you have created your own class with the PHP-CPP library, you can
+    use the same Php::Object class to make instances of it. Because PHP and
+    C++ are different languages, there is a difference between object
+    instances that you should return from your functions (Php::Value or Php::Object 
+    instances), and the variables that you use internally in your C++ code
+    (regular C++ pointers). The PHP-CPP allows you to easily convert these
+    two types.
+</p>
+<p>
+<pre class="language-c++"><code>
+#include &lt;phpcpp.h&gt;
+
+class MyClass : public Php::Base
+{
+    /**
+     *  First factory method
+     *  @return Php::Value      object holding a new MyClass instance
+     */
+    static Php::Value factory1()
+    {
+        // use the Php::Object class to create an instance (this will
+        // result in __construct() being called)
+        return Php::Object("MyClass");
+    }
+    
+    /**
+     *  Alternative factory method
+     *  @return Php::Value
+     */
+    static Php::Value factory2()
+    {
+        // create an instance ourselves
+        MyClass *object = new MyClass();
+        
+        // the object now only exists as C++ object, to ensure that it is also
+        // registered as an object in PHP user space, we wrap it in a 
+        // Php::Object class (which is an extended Php::Value class). Because 
+        // PHP supports reflection it is necessary to also pass in the class 
+        // name. The __construct() method will _not_ be called - because the 
+        // C++ object is already instantiated.
+        return Php::Object("MyClass", object);
+    }
+    
+    /**
+     *  Method that returns 'this' to allow chaining ($x->chain()->chain()).
+     *  @return Php::Value
+     */
+    Php::Value chain()
+    {
+        // the Php::Value has an implicit constructor for Php::Base pointers.
+        // This means that you can safely return 'this' from a method, which
+        // will automatically be converted into a valid Php::Value object. This
+        // works only for pointers to objects that already exist in PHP user
+        // space.
+        return this;
+    }
+    
+    /**
+     *  Method that gets a MyClass instance as parameter
+     *  @param  params      vector holding all parameters
+     */
+    void process(Php::Parameters &amp;params)
+    {
+        // store the first parameter in a Php::Value object
+        Php::Value value = params[0];
+        
+        // if you know for sure that the 'value' variable holds a (wrapped) 
+        // instance of a MyClass object, you can convert the value back into
+        // a pointer to the original C++ object by calling the 'implementation'
+        // method.
+        //
+        // Note that this only works for value objects that hold instances of 
+        // C++ classes defined by your extension! Calling the 'implementation()'
+        // method on a non-object, on an object of a user space class, or of
+        // a core PHP class or a class from a different extension will probably 
+        // result in a crash!
+        MyClass *object = (MyClass *)value.implementation();
+    }
+};
+</code></pre>
 <h2 id="iterating">Iterating</h2>
 <p>
     The Php::Value class implements the begin() and end() methods just like 
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