Recently I contributed a retry functionality to the cache-s3 Haskell project. After I had shared a draft PR with Alexey Kuleshevich, the project's maintainer, he suggested some improvements. In this post shall describe a simplified version of the resulting upstream pull-request and explain how it works.
Mainstream programming languages provide various constructs for control flow: conditionals, loops, exceptions, etc. Many of these can be modeled using the general functor concept. In this post I'm going to show you how.
In most programming languages defining a function (or a method, subroutine, procedure, etc.) is simple. Using this …
Summary: I argue that using a library is the best design pattern. The Haskell ecosystem offers powerful tools for writing concurrent programs.
In a previous post I demonstrated some of Haskell's features to write concurrent programs. I developed a simulated search engine which looked like this:
search30 :: SearchQuery -> IO ()
search30 …Today I went to the talk "Build systems à la carte" of Andrey Mokhov. He presented the results of the identically named paper from last year authored by himself and his co-authors. The following links point to the paper and its related resources:
This is an experience report of playing with Megaparsec, a parser combinator library in Haskell.
The first time I saw a code snippet using the Parsec library I was truly amazed: a parser of Comma-Separated Values(CSV) reads:
csvFile = line `endBy` eol
line = cell `sepBy` (char ',')
cell = quotedCell …In this post we are going to write a simple load balancer in Haskell. The design is based on that presented in Rob Pike's Concurrency Is Not Parallelism talk (starting around 22 minutes). If you are not familiar with this presentation I highly recommend watching it before reading on. Pike …
Thinking using a computer is hard. First, a computer is full of distractions, but let's say we can eliminate those. Second, using the conventional input such as mouse and a keyboard, anything more complex than a character or a mouse click is difficult to communicate to the computer. Where's the …
In this post I solve the Minimum Coin Exchange problem programmatically using Haskell. I will compare the performance of the naive implementation to that using dynamic programming.
The minimum coin exchange problem is generally asked: if we want to make change for \(N\) cents, and we have infinite …
The other day I got a question from a colleague: Do you know an algorithm for this problem of ... details...details? The exact the problem description is not important. It was a well defined problem which totally made sense. I felt that there must be an algorithm for it, but …
In this post I'm replicating in Haskell some of the examples from the talk Go Concurrency Patterns by Rob Pike. In the talk Pike explains how Go's built-in concurrency primitives can help writing concurrent code. I was curious to see how the presented examples would look in Haskell, a language …
© David Wagner 2016
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