CustomCast

This is a PHP extension (built/tested against PHP 8.3) that allows classes to decide how they want to be treated when cast to a boolean, int, or double, instead of using the default behavior.

Usage on a class

A class can define a new magic method, __doCast(CustomCasting\CastableTarget $t), that will get called when the object is cast to a boolean, int, or double. The CastableTarget parameter will indicate the type the object is being cast to - it is an enum, defined as:

enum CastableTarget {
	case CAST_BOOL;
	case CAST_FLOAT;
	case CAST_LONG;
}

the __doCast() method should then return the value that the class wants to be treated as.

Enabling for a class

Once the extension is installed, the INI option custom_cast.use_observer determines if a class needs to manually enable the magic method, or if it will be used automatically (if present). The option defaults to false, on the assumption that it could negatively impact performance to check each class for the magic method. Instead, classes should be annotated with the CustomCasting\CustomCastable attribute to trigger the extension's behavior.

The attribute can be used without any parameters, but a parameter can also be provided to limit the types of casts for which the __doCast() method will be used, by providing a bitflag combination of

• CustomCastable::TARGET_BOOL (use __doCast() for boolean casts)
• CustomCastable::TARGET_FLOAT (use __doCast() for float casts)
• CustomCastable::TARGET_LONG (use __doCast() for integer casts)

If the custom_cast.use_observer INI option is enabled, the attribute is not required, but can still be used to limit the types of casts supported.