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Subject: Re: [PHP-DEV] Ideas on hooking into the object cast handler
From: curt@php.net (Curt Zirzow)

* Thus wrote Robert Silva:
> I'm working on creating object wrappers for native php types. With ZE2 and
> the cast_object object handler, I am able to "unbox" the objects to their
> native php types with simple casts, but as ZE2 currently stands, (to my
> knowledge at least) there is no way to hook into the (object)native_type
> cast. Currently, when you cast a native value to an object using
> (object)$native_val, it calls convert_to_object which simply converts the
> native type to an array. I was hoping some of you more familiar with the ZE
> than I had some ideas of how it may be modified to allow an extension to
> hook into the convert_to_object function. Looked around for some
> implementation of an extension registering a callback inside the engine but
> couldn't find any examples. Here is a userland example of what I am trying
> to accomplish:
> 
> $intObj = new PInt32(5); // Int object wrapper
> $phpInt = (int)$intObj; // Calls the cast_object handler for the PInt32 obj
 
I was actually thinking about this the other day, my idea was to
force an object declaration to tell everyone that it can be casted,
so ZE2 will define all the different type of interfaces:

/* ZE2 defined interface represented in php */
interface Castable {
  function __toString();
  function __toInt();
  function __toFloat();
  function __toArray();
  function __toObject($objname); /* questionable */
}


Then if a object wishes to be converted to a paticular type it
would simply implement the interface:

class Foo implements Castable {
  ...
  function __toString() {
    return "I am a string";
  }
  ...all the rest of the interface definitions
}


The questionable toObject() would provide the possiblities of
something like:

$newObj = (OtherObject) $FooObject;

But, iirc, the above will probably involve a lot of rewriting of
the parsing.



Curt
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