__autoload issues

[gormster]

Okay, so I have a lot of classes I want to autoload. I've got a preferences file which has class names associated with file names, and I've read, at the beginning of my page, that file into an assoc. array named $classes (as class => file). Now, I thought that my __autoload would be pretty simple; it looks like this:

 

<?php
function __autoload($class_name)
{
  require_once(SNOW_CLASS_PATH . $classes[$class_name]);
}
?>

 

Unfortunately this doesn't work. (SNOW_CLASS_PATH, by the way, is the path to the classes folder.) I added a var_dump on $classes in the function, and it gave me a NULL. A little research pointed out that __autoload happens outside any scope, so I guess it can't access any of the variables on the page. Does anyone have a solution? Note that globaling the $classes variable isn't an option since I'm going to be loading classes dynamically.

 

Appreciate your help

-gorman

[emehrkay]

well, is the $classes array global?

[KrisNz]

If I understand correctly, you've got a file that has a hash of class names and their associated file name? Doesn't this mean that every time you write a class you have to go and update that file? To me that somewhat defeats the purpose of having autoload. If you use a naming convention for your classes and their associated filenames you can avoid this altogether.

 

If you camelcase your class names e.g

<?php
class ThisIsMyClass
{
//....
}
?>

Then name the file this_is_my_class.php

 

You can convert the camelcase to the underscored version with this

<?php
function camelToUnderscore($s)
{
   //http://www.regular-expressions.info/refadv.html
   //this translates to
   //look behind(to the right of)  the first character for any upper case
   //character and replace it with an underscore + the matched character
   return strtolower(preg_replace('/(?<=\\w)([A-Z])/', '_\\1', $s));
}
?>

That way you can convert $class_name to its matching file name without needing to keep a reference of it.

 

[gormster]

Okay, the thing is this is basically a framework. Developers add their own classes which conform to an interface. I don't want to limit them to a specific naming convention, particularly as they might have one they already like. That's why I'm using the prefs file/$classes hash. I think I can get around it, though, by just not using __autoload... at the moment the classes are only instantiated once, so I'm just going to add a require_once at that point. I'd still like to do it with __autoload though if anyone has any other ideas.

[KrisNz]

I don't really understand this..

Note that globaling the $classes variable isn't an option since I'm going to be loading classes dynamically.

But you might like to investigate the Registry pattern - this can be used to hold or retrieve a reference to your $classes hash.

[deadimp]

I'm also kinda confused why it can't be global... Global data isn't constant (unless you explicitly define it as such), so you can change it.

 

This auto-include system seems like it'd take a little more maintainence than the developer normally included the file or conformed to naming conventions.

Then again, centralizing the information would help when you reorganize and you don't have to comb through your files again and change your includes.

[448191]

Stop hurting your brains and use classname <> filename mapping.

 

[Daniel0]

I do this:

 

<?php
function __autoload($class_name)
{
require str_replace('_', DIRECTORY_SEPARATOR, $class_name) . '.php';
}
?>

[448191]

That's the classic example: Pear naming convention.

 

Anything goes though (though I do recommend the Pear naming convention).

[Daniel0]

Ah, didn't realize it was that. I haven't really used any pear libraries, but it's the same naming convention in Zend Framework which is the one I find best for PHP.

[448191]

[...] but it's the same naming convention in Zend Framework [...]

 

Yes it is. It's that good.