Tag Archives: object-oriented

Mutable Objects in Kernel

One important difference between Kernel and traditional LISP/Scheme is Kernel’s pervasive use of encapsulated types [1]. There is a clear distinction in Kernel between decomposable structures and opaque objects. Encapsulated types are a significant contributor toward smooth extensibility. They allow the definition of objects, and operations on those object, that are indistinguishable from primitives. We […]

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Fexpr the Ultimate Lambda

This article is dedicated to the memory of John McCarthy (1927–2011) We are constantly on a quest for the elegant combination of simplicity and expressiveness in computer languages—what Alan Kay calls the “Maxwell’s Equations of Software“. An important early milestone was John McCarthy’s LISP [1] (The evolution of these ideas and the thinking behind them […]

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Finger Tree: A Functional Value Object

A Finger Tree is a data-structure that supports amortized O(1) additional and removal of elements from either end [1]. It also can support a large number of common sequence operations, including concatenation, very efficiently. Our implementation is based on the Hinze-Paterson structure [2], simplified for use as a Deque. It is possible to implement a […]

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Message Passing, part 2 – Object-Oriented Method Invocation

This is part two of an article exploring what we mean when we say “message-passing”. Part one described how synchronous rendezvous can be expressed with actors. Part two describes an actor implementation of object-oriented method invocation. For Object-Oriented developers from the Smalltalk tradition, message-passing involves a dynamic method lookup, invocation of that method with the target […]

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