Ruby (programming language)
Matsumoto defined it this way in an interview:Ruby is object-oriented: every value is an object, including classes and instances of types that many other languages designate as primitives (such as integers, booleans, and "null"). Variables always hold references to objects. Every function is a method and methods are always called on an object. Methods defined at the top level scope become methods of the Object class. Since this class is an ancestor of every other class, such methods can be called on any object. They are also visible in all scopes, effectively serving as "global" procedures. Ruby supports inheritance with dynamic dispatch, mixins and singleton methods (belonging to, and defined for, a single instance rather than being defined on the class). Though Ruby does not support multiple inheritance, classes can import modules as mixins.
Data, context and interaction
A Role is a stateless programming construct that corresponds to the end user's mental model of some entity in the system. A Role represents a collection of responsibilities. Whereas vernacular object-oriented programming speaks of objects or classes as the loci of responsibilities, DCI ascribes them to Roles. An object participating in a use case has responsibilities: those that it takes on as a result of playing a particular Role. Most modern programming languages have a way to express Roles, and to express the injection of Role methods into objects, and implementation techniques vary depending on the language. The injection can be fully dynamic at run-time in languages like Ruby and Python; it is more static in languages like Smalltalk-Squeak, Scala and C++. The Qi4j programming environment offers a way to express Role method injection into Java objects. Java 8 default method on interfaces can be used to implement Roles in a typesafe way.