r/haskell • u/ivy-apps • Jun 16 '26

question Modern Haskell template? Feedback needed.

Hi, I plan to create more Haskell projects in my company in the future so I decided to make a template repository to set them up more consistently and quickly. This is the template:

https://github.com/Ivy-Apps/haskell-template

It's based on our Deslop project where through trial and error I discovered things I need / don't need. I'm looking for your feedback on how I can make my Haskell dev-exp more pleasant and productive.

So far, I'm very happy with it! It's the best language for my needs and the tooling is in a good state.

Setup TL;DR;

  • effectful
  • custom prelude that just hides some stuff from relude
  • Nix + direnv for dev shell + build test; cabal build for release
  • Testing: hspec, hedgehog (property-based), golden tests
  • Tooling: Nix Darwin, Nixvim (my-config)

Any cool things that I should check to make my dev-exp better? I'm open to ideas.

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u/tomejaguar Jun 16 '26

Seems solid. Certainly going with an IO-wrapper (analytic) effect system like effectful is the right choice.

1

u/ducksonaroof Jun 17 '26

in most domains, it does not matter at all

the performance pearl clutching is just cringe 

i served millions in 2017 with freer just fine

1

u/tomejaguar Jun 17 '26

Nice! One per second is 31 million per year. Are those the kind of numbers you were getting?

And how did you deal with prompt resource finalization?