Function and Method Errors

  • Cannot add internal functions to return value from get_defined_functions()
  • Cannot add user functions to return value from get_defined_functions()

These errors appear when you've tried to get a value from a function or method that does not return values. The name of the function might suggest that a value would be returned, but the specs should be checked again.

  • Can't use method return value in write context
  • Can't use function return value in write context

Abstract keyword

While a function is abstract it is just a name with no functionality, so there is no point in declaring it static or final.  Conversely, once a function has been developed, it is no longer abstract. Only undeveloped classes or class methods can be declared abstract.

  • Static functions cannot be abstract
  • Cannot use the final modifier on an abstract class member
  • Properties cannot be declared abstract