Doing some sort of ser/deser or encode/decode trick seems ugly and requires you to remember what exactly you did when you are trying to use the constant. I think the class private static variable with accessor is a decent solution, but I'll do you one better. Just have a public static getter method that returns the definition of the constant array. This requires a minimum of extra code and the array definition cannot be accidentally modified.

class UserRoles { public static function getDefaultRoles() { return array('guy', 'development team'); } } initMyRoles( UserRoles::getDefaultRoles() );

If you want to really make it look like a defined constant you could give it an all caps name, but then it would be confusing to remember to add the '()' parentheses after the name.

class UserRoles { public static function DEFAULT_ROLES() { return array('guy', 'development team'); } } //but, then the extra () looks weird... initMyRoles( UserRoles::DEFAULT_ROLES() );

I suppose you could make the method global to be closer to the define() functionality you were asking for, but you really should scope the constant name anyhow and avoid globals.