graninas

At the beginning of 2030, I found this essay in my archives. From what I know today, I think it was very insightful at the moment of writing. And I feel it should be published because it can teach us, Rust developers, how to prevent that sad story from happening again.

---

What killed Haskell, could kill Rust, too

What killed Haskell, could kill Rust, too. Why would I even mention Haskell in this context? Well, Haskell and Rust are deeply related. Not because Rust is Haskell without HKTs. (Some of you know what that means, and the rest of you will wonder for a very long time). Much of the style of Rust is similar in many ways to the style of Haskell. In some sense Rust is a reincarnation of Haskell, with a little bit of C-ish like syntax, a very small amount.

Is Haskell dead?

graninas

Design patterns in Haskell

This is a list of patterns. I'm collecting this list with an idea to write a book similar to the GoF book.

My patterns:

• Typed / Untyped pattern
• Typed Avatar pattern (see Hydra and Node)
  • Typed Options pattern (see EulerHS)
• Control Structure pattern (see CLI control structure in Hydra and similar in Node)

graninas

Haskeller Competency Matrix

See also List of materials about Software Design in Haskell

	Junior	Middle	Senior	Architect
Haskell level	Basic Haskell	Intermediate Haskell	Advanced Haskell	Language-agnostic
Haskell knowledge scope	Learn you a Haskell	Get programming with Haskell	Haskell in Depth	Knows several languages from different categories
	Get programming with Haskell	Haskell in Depth	Functional Design and Architecture
			[Other books on Software Engineering in Haskell](https://github.com/graninas/software-design-in-haskell#B

graninas

data User = User
  { firstName  :: String
  , secondName :: String
  }

-- The User data type has field firstName, it's a string.

-- firstName :: User -> String
-- secondName :: User -> String

graninas

Appendix to Software Design in Haskell

List of materials on Software Design in Haskell

Other resources that are good, but not necessarry about Software Design

Testing

• Testing | Monday Morning Haskell

graninas

Software Design Showcase Projects in Haskell

(WIP)

• Automatic White-Box Testing with Free Monads | Alexander Granin
  • Description: Article and showcase project about an approach to whitebox testing. Describes the idea of recordable and replayable business scenarios based on the Free Monad approach.
  • Design Approach: [Free Monads]
  • Technologies: [free, aeson]
  • Teaches for: How to make a Free monad based business logic recordable and replayable. How to use the recordings for automatic whitebox testing. How to configure this system to do integration testing.

graninas

The Problem

Defining records in Haskell causes accessor functions for the record's fields to be defined. There is no seperate namespace for these accessor functions.

The Goal

Be able to

• use records in Haskell, which share field names.
• use lenses for accessing these fields

graninas

An Opinionated Comparison of Software Design Approaches in Haskell

| | Raw IO | Free Monads; Church Encoded Free Monads | Final Tagless / mtl | Effect Systems | ReaderT

graninas

//
// See https://github.com/louthy/language-ext
// 

using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using LanguageExt;
using static LanguageExt.Prelude;

graninas

{
    "entries": [
      [
        0,
        {
          "tag": "Normal"
        },
        "GenerateGUIDEntry",
        "{\"contents\":{\"guid\":\"662ed4a1-950b-48cd-a91d-1091342070d9\"},\"tag\":\"GenerateGUIDEntry\"}"
      ],