Solving “Same Fringe” with Stream Generators
A classic problem in concurrent programming is known as the “same fringe” problem [1]. What is the same fringe problem? As described by Richard Gabriel [2]: The samefringe problem is this: two binary...
View ArticleEvaluating Expressions, part 6 – Actor Primitives
In part 6 of our series implementing programming language constructs with actors, we explore meta-circular definition of imperative actor primitives. We have now moved beyond expressions which yield...
View ArticleParsing Expression Grammars, part 2
It’s usually not enough to simply recognize patterns in an input stream. Soon we will want to take action based on what we recognize. In order to facilitate this, we will begin creating semantic values...
View ArticleParsing Expression Grammars, part 3
We build on the parsers from part 2 of this series to enhance and extend their capability. In particular, we extend the concept of modular grammars to construct chains of parsers which define a...
View ArticleFinger 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...
View ArticleFutures and Capabilities
In the Actor Model, concurrency is the default. Sequencing must by arranged explicitly. An important case of sequencing occurs when there is a data dependency between different parts of a system. One...
View ArticleProducer/Consumer Rate-Matching
Flow control is a critical feature in a network of asynchronous communicating processes. Our fanciful exploration of a yak-shaving barber’s shop provided us with patterns we can apply to more general...
View Article“Same Fringe” Revisited
The fringe of a binary tree is simply the sequence of leaves reading from left to right [1]. Comparing the fringe of two binary trees to see if they are the same has been described as the simplest...
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