Rewrite count() page (#948)

* Rewrite count() page

* Change methodname to interface name and fix example output

* Add example with Countable object

* Delete redundant code comments

Author: kamil-tekiela

reference/array/functions/count.xml

@@ -4,7 +4,7 @@
 <refentry xml:id="function.count" xmlns="http://docbook.org/ns/docbook">
  <refnamediv>
   <refname>count</refname>
-  <refpurpose>Count all elements in an array, or something in an object</refpurpose>
+  <refpurpose>Counts all elements in an array or in a <interfacename>Countable</interfacename> object</refpurpose>
  </refnamediv>
 
  <refsect1 role="description">
@@ -15,20 +15,9 @@
    <methodparam choice="opt"><type>int</type><parameter>mode</parameter><initializer><constant>COUNT_NORMAL</constant></initializer></methodparam>
   </methodsynopsis>
   <para>
-   Counts all elements in an array, or something in an object.
-  </para>
-  <para>
-   For objects, if you have
-   <link linkend="ref.spl">SPL</link> installed, you can hook into
-   <function>count</function> by implementing interface
-   <classname>Countable</classname>. The interface has exactly one method,
-   <methodname>Countable::count</methodname>, which returns the return value for the
-   <function>count</function> function.
-  </para>
-  <para>
-   Please see the <link linkend="language.types.array">Array</link>
-   section of the manual for a detailed explanation of how arrays
-   are implemented and used in PHP.
+   Counts all elements in an array when used with an array. When used with an
+   object that implements the <interfacename>Countable</interfacename> interface, it returns
+   the return value of the method <methodname>Countable::count</methodname>.
   </para>
  </refsect1>
 
@@ -40,7 +29,7 @@
      <term><parameter>value</parameter></term>
      <listitem>
       <para>
-       An array or <classname>Countable</classname> object.
+       An array or <interfacename>Countable</interfacename> object.
       </para>
      </listitem>
     </varlistentry>
@@ -71,11 +60,11 @@
   &reftitle.returnvalues;
   <para>
    Returns the number of elements in <parameter>value</parameter>.
-   When the parameter is neither an array nor an object with
-   implemented <classname>Countable</classname> interface,
-   <literal>1</literal> will be returned.
-   There is one exception, if <parameter>value</parameter> is &null;,
-   <literal>0</literal> will be returned.
+   Prior to PHP 8.0.0, if the parameter was neither an &array; nor an &object; that
+   implements the <interfacename>Countable</interfacename> interface,
+   <literal>1</literal> would be returned,
+   unless <parameter>value</parameter> was &null;, in which case
+   <literal>0</literal> would be returned.
   </para>
  </refsect1>
 
@@ -112,7 +101,7 @@
  <refsect1 role="examples">
   &reftitle.examples;
   <para>
-   <example>
+   <example xml:id="count.example.basic">
     <title><function>count</function> example</title>
     <programlisting role="php">
 <![CDATA[
@@ -139,7 +128,7 @@ int(3)
    </example>
   </para>
   <para>
-   <example>
+   <example xml:id="count.example.badexample">
     <title><function>count</function> non Countable|array example (bad example - don't do this)</title>
     <programlisting role="php">
 <![CDATA[
@@ -186,7 +175,7 @@ Fatal error: Uncaught TypeError: count(): Argument #1 ($var) must be of type Cou
    </example>
   </para>
   <para>
-   <example>
+   <example xml:id="count.example.recursive">
     <title>Recursive <function>count</function> example</title>
     <programlisting role="php">
 <![CDATA[
@@ -195,14 +184,52 @@ $food = array('fruits' => array('orange', 'banana', 'apple'),
               'veggie' => array('carrot', 'collard', 'pea'));
 
 // recursive count
-echo count($food, COUNT_RECURSIVE); // output 8
+var_dump(count($food, COUNT_RECURSIVE));
 
 // normal count
-echo count($food); // output 2
+var_dump(count($food));
 
 ?>
 ]]>
     </programlisting>
+    &example.outputs;
+    <screen role="php">
+<![CDATA[
+int(8)
+int(2)
+]]>
+    </screen>
+   </example>
+  </para>
+  <para>
+   <example xml:id="count.example.countable">
+    <title><interfacename>Countable</interfacename> object</title>
+    <programlisting role="php">
+<![CDATA[
+<?php
+class CountOfMethods implements Countable
+{
+    private function someMethod()
+    {
+    }
+
+    public function count(): int
+    {
+        return count(get_class_methods($this));
+    }
+}
+
+$obj = new CountOfMethods();
+var_dump(count($obj));
+?>
+]]>
+    </programlisting>
+    &example.outputs;
+    <screen role="php">
+<![CDATA[
+int(2)
+]]>
+    </screen>
    </example>
   </para>
  </refsect1>
@@ -216,6 +243,7 @@ echo count($food); // output 2
     <member><function>empty</function></member>
     <member><function>strlen</function></member>
     <member><function>is_countable</function></member>
+    <member><link linkend="language.types.array">Arrays</link></member>
    </simplelist>
   </para>
  </refsect1>