Computability Theory is the foundation for computer software development. Our programming languages embody the techniques and models described by various theories of computation [1]. The Turing Machine is the canonical example of the Imperative Model [2]. Lambda Calculus is the canonical example of the Functional Model [3]. Kleene’s Church-Turing Thesis asserts the equivalence of these […]
31
Aug
2016
On Separating Values and Effects
Tags: actor, behavior, composition, effect, evaluation, execution, functional, Humus, imperative, lambda-calculus, language, open-system, primitive, real-world, theory, time, value
23
Apr
2012
“Sleeping Barber” in Humus
Tags: actor, asynchronous, blocking, concurrency, consistency, deadlock, Humus, protocol, starvation, state-machine, synchronization
The “Sleeping Barber” problem is another classic concurrency example. As with our previous discussion of “Dining Philosophers”, actors allow a novel approaching to solving this problem. We will adjust a few of the details to enhance the metaphor and have a bit of fun with it. Our metaphorical barber provides yak shaving services. Yaks arrive […]
09
Jan
2011
Playing the Stooge with Humus
Happy New Year and welcome to 2011. With the coming of the new year, I’m happy to announce the availability of a simulator/debugger environment for Humus, (Note: the 2011 version has been archived). Please note that this is a simulator of the Humus language written in JavaScript, so it runs very slowly. It is intended […]
05
Aug
2010
“Dining Philosophers” in Humus
The “Dining Philosophers” problem is a classic example used to illustrate various challenges with concurrency. We will approach this problem by incrementally designing the actors which model the problem and its solution in Humus. Through this example we will explore the avoidance of deadlock and starvation in the design of actor-based systems. Basic Thinking/Eating Cycle […]