note 35685 added to function.eval
| From: | lclkk at urbanvagabond dot net | Date: | Thu, 11 Sep 2003 03:04:50 +0000 |
| Subject: | note 35685 added to function.eval | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-56043@lists.php.net to get a copy of this message | ||
You can use eval() to pass variable-length parameter lists to arbitrary functions by using
func_get_args() to build the required code. This approach can sometimes be preferable to using an
array. The example below defines a function capable of instantiating objects whose constructors
expect different numbers of parameters.
<?php
function classFactory($classname)
{
$code = "return new {$classname}(";
if (func_num_args() > 1) {
$params = array_slice(func_get_args(),1);
$c = count($params);
for($i=0;$i<$c;++$i) {
if ($i>0) {
$code .= ',';
}
$code .= '$params[' . $i . ']';
}
}
$code .= ');';
return eval($code);
}
class Foo
{
function Foo($arg1,$arg2,$arg3)
{
echo "I am Foo, I expect 3 arguments...\n";
echo "arg1 = $arg1\n";
echo "arg2 = $arg2\n";
echo "arg3 = $arg3\n\n";
}
}
class Bar
{
function Bar($arg1)
{
echo "I am Bar, I expect 1 argument...\n";
echo "arg1 = $arg1\n\n";
}
}
$myFoo = classFactory('Foo',100,'moose',array(1,2,3));
$myBar = classFactory('Bar',4564);
?>
----
Manual Page -- http://www.php.net/manual/en/function.eval.php
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