RSS Parrot

Song recommendations with pipes and filters

https://blog.ploeh.dk/2025/07/14/song-recommendations-with-pipes-and-filters/

Published: July 14, 2025 14:52

Composing small Recawr Sandwiches. This article is part of a larger series that outlines various alternative ways to design with functional programming. That (first) article contains a table of contents, as well as outlines the overall…

A parser and interpreter for a very small language

https://blog.ploeh.dk/2025/07/07/a-parser-and-interpreter-for-a-very-small-language/

Published: July 7, 2025 06:39

A single Haskell script file. I recently took the final exam in a course on programming language design. One of the questions was about a tiny language, and since this was a take-home exam running over many days, I had time to spare.…

Song recommendations from Haskell combinators

https://blog.ploeh.dk/2025/06/30/song-recommendations-from-haskell-combinators/

Published: June 30, 2025 05:54

Traversing lists of IO. A refactoring. This article is part of a series named Alternative ways to design with functional programming. In the previous article, you saw how to refactor the example code base to a composition of standard F#…

Song recommendations from F# combinators

https://blog.ploeh.dk/2025/06/23/song-recommendations-from-f-combinators/

Published: June 23, 2025 05:49

Traversing sequences of tasks. A refactoring. This article is part of a series named Alternative ways to design with functional programming. In the previous article, you saw how to refactor the example code base to a composition of…

Song recommendations from C# combinators

https://blog.ploeh.dk/2025/06/16/song-recommendations-from-c-combinators/

Published: June 16, 2025 07:41

LINQ-style composition, including SelectMany and Traverse. This article is part of a larger series titled Alternative ways to design with functional programming. In the previous article, I described, in general terms, a pragmatic…

Song recommendations from combinators

https://blog.ploeh.dk/2025/06/09/song-recommendations-from-combinators/

Published: June 9, 2025 14:02

Interleaving impure actions with pure functions. Not really functional programming. This article is part of a larger article series about alternative ways to design with functional programming, particularly when faced with massive data…

Testing races with a slow Decorator

https://blog.ploeh.dk/2025/06/02/testing-races-with-a-slow-decorator/

Published: June 2, 2025 08:03

Delaying database interactions for test purposes. In chapter 12 in Code That Fits in Your Head, I cover a typical race condition and how to test for it. The book comes with a pedagogical explanation of the problem, including a diagram in…

Song recommendations as a Haskell Impureim Sandwich

https://blog.ploeh.dk/2025/05/26/song-recommendations-as-a-haskell-impureim-sandwich/

Published: May 26, 2025 07:15

A pure function on potentially massive data. This article is part of a larger article series called Alternative ways to design with functional programming. As the title suggests, these articles discuss various ways to apply…

Song recommendations as an F# Impureim Sandwich

https://blog.ploeh.dk/2025/05/19/song-recommendations-as-an-f-impureim-sandwich/

Published: May 19, 2025 08:06

A pure function on potentially massive data. This article is part of a larger article series titled Alternative ways to design with functional programming. In the previous article, you saw an example of applying the Impureim Sandwich…

Song recommendations proof-of-concept memory measurements

https://blog.ploeh.dk/2025/05/12/song-recommendations-proof-of-concept-memory-measurements/

Published: May 12, 2025 07:52

An attempt at measurement, and some results. This is an article in a larger series about functional programming design alternatives, and a direct continuation of the previous article. The question lingering after the Impureim Sandwich…