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In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
Classes can have multiple superclasses, a list of slots (member variables in C++/Java parlance) and a special metaclass. Slots can be allocated by class (all instances of a class share the slot) or by instance. Each slot has a name and the value of a slot can be accessed by that name using the function slot-value. Additionally special generic ...
A method is a behavior of an object parametrized by a user. Data is represented as properties of the object, and behaviors are represented as methods. For example, a Window object could have methods such as open and close, while its state (whether it is open or closed at any given point in time) would be a property.
In Perl, a return value or values of a subroutine can depend on the context in which it was called. The most fundamental distinction is a scalar context where the calling code expects one value, a list context where the calling code expects a list of values and a void context where the calling code doesn't expect any return value at all. A ...
The class defines the data format, like variables (e.g., name, age) and methods (actions the object can take). Every instance of the class has the same set of variables and methods. Objects are created using a special method in the class known as a constructor. Here are a few key terms in class-based OOP:
PHP defines the "magic methods" __getand__set for properties of objects. [9] In this example of a simple class representing a student with only the name stored, one can see the variable name is private, i.e. only visible from the Student class, and the "setter" and "getter" is public, namely the getName() and setName('name') methods.
In some programming languages, function overloading or method overloading is the ability to create multiple functions of the same name with different implementations. Calls to an overloaded function will run a specific implementation of that function appropriate to the context of the call, allowing one function call to perform different tasks ...
class name definition «inheriting from parentclass». «interfaces: interfaces.» method_and_field_declarations endclass. class name implementation. method_implementations endclass. interface name . members endinterface.