https://www.pistack.xyz/tags/effect-systems/ Recent content in Effect-Systems on Pi Stack Hugo en-us Sat, 19 Sep 2026 00:00:00 +0000 https://www.pistack.xyz/posts/2026-09-19-haskell-effect-systems-effectful-polysemy-fused-effects-mtl/ Sat, 19 Sep 2026 00:00:00 +0000 https://www.pistack.xyz/posts/2026-09-19-haskell-effect-systems-effectful-polysemy-fused-effects-mtl/ <p>Your <code>App</code> monad has grown to nine stacked transformers, the type signatures no longer fit on one line, and every new capability forces you to edit a <code>MonadFoo</code> instance chain that nobody on the team fully understands. That is the exact pain every Haskell team hits somewhere between 5k and 50k lines — and it is why effect systems exist.</p>