Sophie: php-manual-en-4.3.0-2mdk noarch

php-manual-en-4.3.0-2mdk.noarch.rpm

<HTML
><HEAD
><TITLE
>Variable functions</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
REL="HOME"
TITLE="PHP Manual"
HREF="index.html"><LINK
REL="UP"
TITLE="Functions"
HREF="functions.html"><LINK
REL="PREVIOUS"
TITLE="old_function"
HREF="functions.old-syntax.html"><LINK
REL="NEXT"
TITLE="Classes and Objects"
HREF="language.oop.html"><META
HTTP-EQUIV="Content-type"
CONTENT="text/html; charset=ISO-8859-1"></HEAD
><BODY
CLASS="sect1"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>PHP Manual</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="functions.old-syntax.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 13. Functions</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="language.oop.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="functions.variable-functions"
></A
>Variable functions</H1
><P
>&#13;    PHP supports the concept of variable functions. This means that if
    a variable name has parentheses appended to it, PHP will look for
    a function with the same name as whatever the variable evaluates
    to, and will attempt to execute it. Among other things, this can
    be used to implement callbacks, function tables, and so forth.
   </P
><P
>&#13;    Variable functions won't work with language constructs such 
    as <A
HREF="function.echo.html"
><B
CLASS="function"
>echo()</B
></A
>, <A
HREF="function.print.html"
><B
CLASS="function"
>print()</B
></A
>,
    <A
HREF="function.unset.html"
><B
CLASS="function"
>unset()</B
></A
>, <A
HREF="function.isset.html"
><B
CLASS="function"
>isset()</B
></A
>,
    <A
HREF="function.empty.html"
><B
CLASS="function"
>empty()</B
></A
>, <A
HREF="function.include.html"
><B
CLASS="function"
>include()</B
></A
>,
    <A
HREF="function.require.html"
><B
CLASS="function"
>require()</B
></A
> and the like. You need to use
    your own wrapper function to utilize any of these constructs
    as variable functions.
   </P
><P
>&#13;    <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN5416"
></A
><P
><B
>Example 13-3. Variable function example</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="php"
>&#60;?php
function foo()
{
    echo "In foo()&#60;br&#62;\n";
}

function bar($arg = '')
{
    echo "In bar(); argument was '$arg'.&#60;br&#62;\n";
}

// This is a wrapper function around echo
function echoit($string)
{
    echo $string;
}

$func = 'foo';
$func();        // This calls foo()

$func = 'bar';
$func('test');  // This calls bar()

$func = 'echoit';
$func('test');  // This calls echoit()
?&#62;</PRE
></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
   </P
><P
>&#13;    You can also call an object's method by using the variable functions
    feature.
    <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN5420"
></A
><P
><B
>Example 13-4. Variable method example</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="php"
>&#60;?php
class Foo
{
    function Var()
    {
        $name = 'Bar';
        $this-&#62;$name(); // This calls the Bar() method
    }
    
    function Bar()
    {
        echo "This is Bar";
    }
}

$foo = new Foo();
$funcname = "Var";
$foo-&#62;$varname();   // This calls $foo-&#62;Var()

?&#62;</PRE
></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
   </P
><P
>&#13;    See also <A
HREF="function.call-user-func.html"
><B
CLASS="function"
>call_user_func()</B
></A
>,
    <A
HREF="language.variables.variable.html"
>&#13;    variable variables</A
> and <A
HREF="function.function-exists.html"
><B
CLASS="function"
>function_exists()</B
></A
>.
   </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="functions.old-syntax.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="language.oop.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><TT
CLASS="literal"
>old_function</TT
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="functions.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Classes and Objects</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>