Multiple inheritanceMultiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or class may only inherit from one particular object or class. Multiple inheritance has been a controversial issue for many years, with opponents pointing to its increased complexity and ambiguity in situations such as the "diamond problem", where it may be ambiguous as to which parent class a particular feature is inherited from if more than one parent class implements said feature.
Icon (programming language)Icon is a very high-level programming language based on the concept of "goal-directed execution" in which code returns a "success" along with valid values, or a "failure", indicating that there is no valid data to return. The success and failure of a given block of code is used to direct further processing, whereas conventional languages would typically use boolean logic written by the programmer to achieve the same ends. Because the logic for basic control structures is often implicit in Icon, common tasks can be completed with less explicit code.
Self (programming language)Self is an object-oriented programming language based on the concept of prototypes. Self began as a dialect of Smalltalk, being dynamically typed and using just-in-time compilation (JIT) as well as the prototype-based approach to objects: it was first used as an experimental test system for language design in the 1980s and 1990s. In 2006, Self was still being developed as part of the Klein project, which was a Self virtual machine written fully in Self. The latest version is 2017.1 released in May 2017.
SqueakSqueak is an object-oriented, class-based, and reflective programming language. It was derived from Smalltalk-80 by a group that included some of Smalltalk-80's original developers, initially at Apple Computer, then at Walt Disney Imagineering, where it was intended for use in internal Disney projects. The group would later go on to be supported by HP labs, SAP, and most recently, Y Combinator. Squeak runs on a virtual machine (VM), allowing for a high degree of portability.
Late bindingIn computing, late binding or dynamic linkage—though not an identical process to dynamically linking imported code libraries—is a computer programming mechanism in which the method being called upon an object, or the function being called with arguments, is looked up by name at runtime. In other words, a name is associated with a particular operation or object at runtime, rather than during compilation. The name dynamic binding is sometimes used, but is more commonly used to refer to dynamic scope.
MetaclassIn object-oriented programming, a metaclass is a class whose instances are classes. Just as an ordinary class defines the behavior of certain objects, a metaclass defines the behavior of certain classes and their instances. Not all object-oriented programming languages support metaclasses. Among those that do, the extent to which metaclasses can override any given aspect of class behavior varies. Metaclasses can be implemented by having classes be first-class citizens, in which case a metaclass is simply an object that constructs classes.
Scratch (programming language)Scratch is a high-level block-based visual programming language and website aimed primarily at children as an educational tool, with a target audience of ages 8 to 16. Users on the site, called Scratchers, can create projects on the website using a block-like interface. Projects can be exported to standalone HTML5, Android apps, Bundle (macOS) and EXE files using external tools. Scratch was conceived and designed through collaborative National Science Foundation grants awarded to Mitchell Resnick and Yasmin Kafai.
Etoys (programming language)Etoys is a child-friendly computer environment and object-oriented prototype-based programming language for use in education. Etoys is a media-rich authoring environment with a scripted object model for many different objects that runs on different platforms and is free and open source. Squeak was originally developed at Apple in 1996 by Dan Ingalls. Squeak is a Smalltalk implementation, object-oriented, class-based, and reflective, derived from Smalltalk-80 at Apple Computer.
