philip Fri Jul 18 01:43:49 2003 EDT
Modified files:
/phpdoc/en/language variables.xml
Log:
Created sections for static and global as requested in bug #16234. Also
made informal examples formal.
Index: phpdoc/en/language/variables.xml
diff -u phpdoc/en/language/variables.xml:1.67 phpdoc/en/language/variables.xml:1.68
--- phpdoc/en/language/variables.xml:1.67 Sun Jul 6 12:40:27 2003
+++ phpdoc/en/language/variables.xml Fri Jul 18 01:43:49 2003
@@ -1,5 +1,5 @@
<?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.67 $ -->
+<!-- $Revision: 1.68 $ -->
<chapter id="language.variables">
<title>Variables</title>
@@ -362,11 +362,18 @@
This can cause some problems in that people may inadvertently
change a global variable. In PHP global variables must be
declared global inside a function if they are going to be used in
- that function. An example:
+ that function.
</simpara>
-
- <informalexample>
- <programlisting role="php">
+
+ <sect2 id="language.variables.scope.global">
+ <title>The global keyword</title>
+ <simpara>
+ First, an example use of <literal>global</literal>:
+ </simpara>
+ <para>
+ <example>
+ <title>Using global</title>
+ <programlisting role="php">
<![CDATA[
<?php
$a = 1;
@@ -383,8 +390,9 @@
echo $b;
?>
]]>
- </programlisting>
- </informalexample>
+ </programlisting>
+ </example>
+ </para>
<simpara>
The above script will output "3". By declaring
@@ -399,9 +407,10 @@
the special PHP-defined <varname>$GLOBALS</varname> array. The
previous example can be rewritten as:
</simpara>
-
- <informalexample>
- <programlisting role="php">
+ <para>
+ <example>
+ <title>Using <varname>$GLOBALS</varname> instead of global</title>
+ <programlisting role="php">
<![CDATA[
<?php
$a = 1;
@@ -416,8 +425,9 @@
echo $b;
?>
]]>
- </programlisting>
- </informalexample>
+ </programlisting>
+ </example>
+ </para>
<simpara>
The <varname>$GLOBALS</varname> array is an associative array with
@@ -429,9 +439,9 @@
Here's an example demonstrating the power of superglobals:
</simpara>
<para>
-
- <informalexample>
- <programlisting role="php">
+ <example>
+ <title>Example demonstrating superglobals and scope</title>
+ <programlisting role="php">
<![CDATA[
<?php
function test_global()
@@ -450,9 +460,12 @@
?>
]]>
</programlisting>
- </informalexample>
+ </example>
</para>
-
+ </sect2>
+
+ <sect2 id="language.variables.scope.static">
+ <title>Using static variables</title>
<simpara>
Another important feature of variable scoping is the
<emphasis>static</emphasis> variable. A static variable exists
@@ -460,9 +473,10 @@
when program execution leaves this scope. Consider the following
example:
</simpara>
-
- <informalexample>
- <programlisting role="php">
+ <para>
+ <example>
+ <title>Example demonstrating need for static variables</title>
+ <programlisting role="php">
<![CDATA[
<?php
function Test ()
@@ -473,9 +487,9 @@
}
?>
]]>
- </programlisting>
- </informalexample>
-
+ </programlisting>
+ </example>
+ </para>
<simpara>
This function is quite useless since every time it is called it
sets <varname>$a</varname> to <literal>0</literal> and prints
@@ -485,9 +499,10 @@
counting function which will not lose track of the current count,
the <varname>$a</varname> variable is declared static:
</simpara>
-
- <informalexample>
- <programlisting role="php">
+ <para>
+ <example>
+ <title>Example use of static variables</title>
+ <programlisting role="php">
<![CDATA[
<?php
function Test()
@@ -498,9 +513,9 @@
}
?>
]]>
- </programlisting>
- </informalexample>
-
+ </programlisting>
+ </example>
+ </para>
<simpara>
Now, every time the Test() function is called it will print the
value of <varname>$a</varname> and increment it.
@@ -515,9 +530,10 @@
simple function recursively counts to 10, using the static
variable <varname>$count</varname> to know when to stop:
</simpara>
-
- <informalexample>
- <programlisting role="php">
+ <para>
+ <example>
+ <title>Static variables with recursive functions</title>
+ <programlisting role="php">
<![CDATA[
<?php
function Test()
@@ -533,13 +549,19 @@
}
?>
]]>
- </programlisting>
- </informalexample>
+ </programlisting>
+ </example>
+ </para>
+ </sect2>
+ <sect2 id="language.variables.scope.references">
+ <title>References with global and static variables</title>
<simpara>
The Zend Engine 1, driving <literal>PHP4</literal>, implements the
- <literal>static</literal> and <literal>global</literal> modifier for
- variables in terms of references. For example, a true global variable
+ <link linkend="language.variables.scope.static">static</link> and
+ <link linkend="language.variables.scope.global">global</link> modifier
+ for variables in terms of <link linkend="language.references">
+ references</link>. For example, a true global variable
imported inside a function scope with the <literal>global</literal>
statement actually creates a reference to the global variable. This can
lead to unexpected behaviour which the following example addresses:
@@ -643,8 +665,7 @@
variable, it's not <emphasis>remembered</emphasis> when you call the
<literal>&get_instance_ref()</literal> function a second time.
</simpara>
-
-
+ </sect2>
</sect1>
<sect1 id="language.variables.variable">
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