polysemy
:gemini: higher-order, no-boilerplate monads (by polysemy-research)
haskell.nix
Alternative Haskell Infrastructure for Nixpkgs (by input-output-hk)
polysemy | haskell.nix | |
---|---|---|
7 | 16 | |
1,054 | 591 | |
0.8% | 0.7% | |
6.2 | 9.7 | |
3 months ago | 1 day ago | |
Haskell | Nix | |
BSD 3-clause "New" or "Revised" License | Apache License 2.0 |
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
polysemy
Posts with mentions or reviews of polysemy.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2023-06-02.
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Functional Declarative Design: A Comprehensive Methodology for Statically-Typed Functional Programming Languages
Thirdly, composing arbitrary effects without losing state is really, really difficult. Things are fine when you limit yourself to State and Reader, sure, but once you start with nondeterminism you’ll discover it’s shockingly easy to produce behaviors that are baffling unless you’ve spent a preposterous amount of time thinking about this stuff. (I’ve been bitten in prod by silent state-dropping bugs, and rarely have I been more flummoxed.) Consider this example, which produces silent changes in the semantics of <|> depending on whether you use it inside or outside of a higher-order effect. Every single effect library (besides the still-unreleased eff) gets certain combinations of effects + nondeterminism wrong. You could make the argument that most people don’t use nondeterministic monads, but eDSLs really shine when you have access to them, as you can turn a concrete interpreter to an abstract one fairly easily.
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Introduction to Doctests in Haskell
Looking for a few projects that make use of it, I found accelerate, hawk, polysemy and pretty-simple, so I'll be interested to poke around in their code and see how they have things set up.
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ReaderT pattern is just extensible effects
Right, I think I'll just give it a shot to see. Polysemy is nice but I'm still having trouble getting what I want out of it (which may very well be entirely a fault of my own understanding)
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Where's more discussion of the designs of effect systems?
Languages such as Koka only support algebraic effects, not scoping operations such as catch and listen. The Effect Handlers in Scope paper introduces scoping operations, which lead to the Haskell libraries fused-effects and polysemy, but they turned out to have some weird semantics. eff is her effort to fix that.
- Monthly Hask Anything (June 2021)
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Trouble Reinterpreting Higher Order Effects in PolySemy
Looking at the interpreter for Reader might give some clues if this doesn't work. https://github.com/polysemy-research/polysemy/blob/master/src/Polysemy/Reader.hs#L38-L45
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Structuring Code with ZIO & ZLayers
*But I'm not terribly well versed in Scala's other DI offerings. I came from Haskell and didn't find anything in Scala that clicked with me until I found ZIO. It reminded me a lot of my favorite way of writing Haskell programs (https://github.com/polysemy-research/polysemy)—albeit with a completely different implementation.
haskell.nix
Posts with mentions or reviews of haskell.nix.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2025-05-20.
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Haskell Project Template with Nix Flakes
Haskell.nix -- a more flexible but complex option from IOHK.
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Why does Nix have Haskell packages that are incompatible with GHC for a given version?
I'm not a great haskeller but I found haskell.nix better for Haskell projects, like the commenter on Discourse suggested. I've had a few issued regarding package versions with nixpkgs that haskell.nix solved.
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Simple GHC stack for a novice
FWIW, there's also libraries like haskell.nix that solve the caching problem.
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Any up-to-date cross-compiling methods for Raspberry Pi?
I would try haskell.nix.
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Take the Nix Pill
If you want to hurt your brain, check out haskell.nix. That's some good stuff right there ^^
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Trying to build a statically linked binary against glibc (Linux)
The haskell.nix framework is good for this.
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GHC 9.4.1 Windows changes
One cool thing is that this will enable GHC builds using ucrt instead of vscrt in the future. Concretely, together with NixOS/nixpkgs#171418 and its follow-up NixOS/nixpkgs#173498), this will e.g. allow haskell.nix to upgrade to a newer wine pin for TH cross compilation: https://github.com/input-output-hk/haskell.nix/blob/dd13e822529ae5342494969bce8a457522a60100/overlays/wine.nix
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How to make stack work like it's supposed to
I've been using IOHK's alternative infrastructure for this reason. It has its quirks but I've been happier with it. Before that I think I was using developPackage from the nixpkgs haskell tooling which had some introspection ability. You may consider trying that out. But as I remember this will not abide by your version bounds.
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Announcing `safe-coloured-text`
There's a lot to like here. Alas, despite minimal dependencies, terminfo is somehow uniquely problematic in haskell.nix.
- A question about the current state of Haskell running natively on Apple silicon:
What are some alternatives?
When comparing polysemy and haskell.nix you can also consider the following projects:
ast-monad - A library for constructing AST by using do-notation
nixkell - A simple Nix-Haskell skeleton
purescript - A strongly-typed language that compiles to JavaScript
Cabal - Official upstream development repository for Cabal and cabal-install
freer-simple - A friendly effect system for Haskell
ghc-whole-program-compiler-project - GHC Whole Program Compiler and External STG IR tooling