New examples for classes (#750)

Co-authored-by: Anna Filina <afilina@gmail.com>

reference/classobj/examples.xml

@@ -6,62 +6,66 @@
  <para>
   In this example, we first define a base class and an extension
   of the class. The base class describes a general vegetable,
-  whether it is edible or not and what is its color. The subclass
+  whether it is edible, and what is its color. The subclass
   <varname>Spinach</varname> adds a method to cook it and another to
   find out if it is cooked.
  </para>
  <para>
   <example>
-   <title>classes.inc</title>
+   <title>Class Definitions</title>
+   <para><varname>Vegetable</varname></para>
    <programlisting role="php">
 <![CDATA[
 <?php
 
-// base class with member properties and methods
 class Vegetable {
+    public $edible;
 
-   var $edible;
-   var $color;
+    public $color;
 
-   function __construct($edible, $color="green")
-   {
-       $this->edible = $edible;
-       $this->color = $color;
-   }
+    public function __construct($edible, $color = "green")
+    {
+        $this->edible = $edible;
+        $this->color = $color;
+    }
 
-   function is_edible()
-   {
-       return $this->edible;
-   }
+    public function isEdible()
+    {
+        return $this->edible;
+    }
 
-   function what_color()
-   {
-       return $this->color;
-   }
+    public function getColor()
+    {
+        return $this->color;
+    }
+}
 
-} // end of class Vegetable
+?>
+]]>
+   </programlisting>
+   <para><varname>Spinach</varname></para>
+   <programlisting role="php">
+<![CDATA[
+<?php
 
-// extends the base class
 class Spinach extends Vegetable {
+    public $cooked = false;
 
-   var $cooked = false;
+    public function __construct()
+    {
+        parent::__construct(true, "green");
+    }
 
-   function __construct()
-   {
-       parent::__construct(true, "green");
-   }
+    public function cook()
+    {
+        $this->cooked = true;
+    }
 
-   function cook_it()
-   {
-       $this->cooked = true;
-   }
-
-   function is_cooked()
-   {
-       return $this->cooked;
-   }
-
-} // end of class Spinach
+    public function isCooked()
+    {
+        return $this->cooked;
+    }
+}
 
 ?>
 ]]>
@@ -79,40 +83,37 @@ class Spinach extends Vegetable {
    <title>test_script.php</title>
    <programlisting role="php">
 <![CDATA[
-<pre>
 <?php
 
-include "classes.inc";
+// register autoloader to load classes
+spl_autoload_register();
 
-// utility functions
-
-function print_vars($obj)
+function printProperties($obj)
 {
-foreach (get_object_vars($obj) as $prop => $val) {
-    echo "\t$prop = $val\n";
-}
+    foreach (get_object_vars($obj) as $prop => $val) {
+        echo "\t$prop = $val\n";
+    }
 }
 
-function print_methods($obj)
+function printMethods($obj)
 {
-$arr = get_class_methods(get_class($obj));
-foreach ($arr as $method) {
-    echo "\tfunction $method()\n";
-}
+    $arr = get_class_methods(get_class($obj));
+    foreach ($arr as $method) {
+        echo "\tfunction $method()\n";
+    }
 }
 
-function class_parentage($obj, $class)
+function objectBelongsTo($obj, $class)
 {
-if (is_subclass_of($GLOBALS[$obj], $class)) {
-    echo "Object $obj belongs to class " . get_class($GLOBALS[$obj]);
-    echo ", a subclass of $class\n";
-} else {
-    echo "Object $obj does not belong to a subclass of $class\n";
-}
+    if (is_subclass_of($obj, $class)) {
+        echo "Object belongs to class " . get_class($obj);
+        echo ", a subclass of $class\n";
+    } else {
+        echo "Object does not belong to a subclass of $class\n";
+    }
 }
 
 // instantiate 2 objects
-
 $veggie = new Vegetable(true, "blue");
 $leafy = new Spinach();
 
@@ -123,34 +124,47 @@ echo ", PARENT " . get_parent_class($leafy) . "\n";
 
 // show veggie properties
 echo "\nveggie: Properties\n";
-print_vars($veggie);
+printProperties($veggie);
 
 // and leafy methods
 echo "\nleafy: Methods\n";
-print_methods($leafy);
+printMethods($leafy);
 
 echo "\nParentage:\n";
-class_parentage("leafy", "Spinach");
-class_parentage("leafy", "Vegetable");
+objectBelongsTo($leafy, Spinach::class);
+objectBelongsTo($leafy, Vegetable::class);
+
 ?>
-</pre>
 ]]>
    </programlisting>
+   &examples.outputs;
+   <screen>
+<![CDATA[
+veggie: CLASS Vegetable
+leafy: CLASS Spinach, PARENT Vegetable
+
+veggie: Properties
+        edible = 1
+        color = blue
+
+leafy: Methods
+        function __construct()
+        function cook()
+        function isCooked()
+        function isEdible()
+        function getColor()
+
+Parentage:
+Object does not belong to a subclass of Spinach
+Object belongs to class Spinach, a subclass of Vegetable
+]]>
+   </screen>
    <para>
     One important thing to note in the example above is that
     the object <varname>$leafy</varname> is an instance of the class
     <classname>Spinach</classname> which is a subclass of
-    <classname>Vegetable</classname>,
-    therefore the last part of the script above will output:
+    <classname>Vegetable</classname>.
    </para>
-   <screen>
-<![CDATA[
-   [...]
-Parentage:
-Object leafy does not belong to a subclass of Spinach
-Object leafy belongs to class spinach, a subclass of Vegetable
-]]>
-   </screen>
   </example>
  </para>
 </appendix>
@@ -175,4 +189,3 @@ vim600: syn=xml fen fdm=syntax fdl=2 si
 vim: et tw=78 syn=sgml
 vi: ts=1 sw=1
 -->
-