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.
Uniform access principle
Strictly speaking, Ruby does not follow Meyer's original UAP in that the syntax for accessing an attribute is different from the syntax for invoking a method. But here, the access for an attribute will always actually be through a function which is often automatically generated. So in essence, either type of access invokes a function and the language does follow Meyer's revised Uniform Access Principle.