Using OR operator when defining property in class

I am making an abstract class to ease up handling of properties.

Now I want to set some constant options to a property using the binary OR ( | ) operator.

class VarType
{
    // Variable types
    const MIXED         = 0;
    const STRING        = 1;
    const INT           = 2;
    const FLOAT         = 3;
    const BOOL          = 4;
    const ARRAY_VAL     = 5;
    const OBJECT        = 6;
    const DATETIME      = 7;

    // Variable开发者_Python百科 modes
    const READ_ONLY     = 16;
    const NOT_NULL      = 32;
}

class myClass {
    protected $_property = 'A string of text';
    protected $_property__type = VarType::STRING | VarType::READ_ONLY;
}

This returns the following error:

Parse error: syntax error, unexpected '|'

How can I do this without having to type:

protected $_property__type = 17;

---

You could initialise the member's value in a constructor.

Yes, it's a bit minging. IMO the language should allow the expression here as the values are constants, but it does not. C++ fixes things like this in C++0x with constexpr, but that doesn't help you here. :)

---

declare protected fields in __construct() or, if it is static class, use 'define' before class declaration:

define('myClass_property_type', VarType::STRING | VarType::READ_ONLY);

class myClass {
    protected $_property = 'A string of text';
    protected $_property__type = myClass_property_type;
}

But it's "dirty" method, don't use it for non-static class and try to avoid using it for any class.

---

It's not possible to declare it like that.

You can use your constructor to initialize the property.

---

Instead of what you're doing, try

(for static members, that is scoped to the class, shared across all instances)

class myClass {
    protected static $_property;
    protected static $_property__type;
}

myClass::$_property = 'A string of text';
myClass::$_property__type = VarType::STRING | VarType::READ_ONLY;

(for normal, non-static member variables)

class  myClass {
     function __construct()
     { 
         $this->_property = "A string of text";
         $this->_property__type = VarType::STRING | VarType::READ_ONLY;
     }

 ...
 }