errors VS recursion-schemes

Compare errors vs recursion-schemes and see what are their differences.


Type-safe error handling (by Gabriella439)


Generalized bananas, lenses and barbed wire (by ekmett)
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errors recursion-schemes
0 20
63 333
- 0.3%
3.1 5.0
5 months ago 4 months ago
Haskell Haskell
BSD 3-clause "New" or "Revised" License BSD 2-clause "Simplified" License
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.


Posts with mentions or reviews of errors. We have used some of these posts to build our list of alternatives and similar projects.

We haven't tracked posts mentioning errors yet.
Tracking mentions began in Dec 2020.


Posts with mentions or reviews of recursion-schemes. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-12-05.
  • -❄️- 2023 Day 4 Solutions -❄️-
    143 projects | /r/adventofcode | 5 Dec 2023
    Reasonably proud of my part 2 solution, although would like to try using a recursion scheme rather than unstructured recursion:
  • Interactive animations
    11 projects | /r/haskell | 6 May 2023
    Yeah, that project is pretty much at the bottom of my list, unfortunately. My top projects these days are mgmt, klister, recursion-schemes, and hint... And that's already too much!
  • Is there a way to avoid call overhead?
    5 projects | /r/rust | 10 Sep 2022
    Maybe I didn't link the best post. It is unfortunately the only one I know that uses Rust. If you are able to read Haskell, the documentation for the recursion-schemes package might be a better resource?
  • So you come across an undocumented library…
    2 projects | /r/haskell | 16 Nov 2021
    But wait, there's more! One of the two challenges was the recursion-schemes library. I wrote some examples, but the output I was getting from that example was not what I expected. I dug further, and it turned out to be a bug in the library! In addition to the documentation, I thus also worked on a fix for that bug.
    2 projects | /r/haskell | 16 Nov 2021
    It's a pretty complicated bug, documented in details at
  • Beautiful ideas in programming: generators and continuations
    2 projects | | 3 Aug 2021
    It’s also trivial and easy in Haskell — you just need an instance of `Foldable` or `Traversable` on your collection, and then you can fold or traverse it in a configurable way. Or for recursive structures, use Or even just pass a traversal function as an argument for maximum flexibility.
  • Seeking a Project Lead for Matchmaker - Haskell Foundation
    3 projects | /r/haskell | 26 Jul 2021
    Yes please! Right now all of my open-source projects (most notably hint and recursion-schemes) are about to drop into barely-updated mode, and while I knew this would happen and have been working towards finding co-maintainers, I am now realizing that it wasn't enough. I think such a website would definitely have helped, and I am hoping that once it launches, I'll be able to use it to find some co-maintainers to tide over my projects until I become available again.
  • Question about composing functors, functor products, comonads and recursion schemes
    2 projects | /r/haskell | 1 Apr 2021
    I wouldn't bother with gfold, it's broken and rarely used. I'd start from a simpler implementation of zygo:

What are some alternatives?

When comparing errors and recursion-schemes you can also consider the following projects:


distributed-process-platform - DEPRECATED (Cloud Haskell Platform) in favor of distributed-process-extras, distributed-process-async, distributed-process-client-server, distributed-process-registry, distributed-process-supervisor, distributed-process-task and distributed-process-execution

record - Anonymous records

unliftio - The MonadUnliftIO typeclass for unlifting monads to IO

machines - Networks of composable stream transducers

pipes-core - Compositional pipelines

chr-core - Constraint Handling Rules

freer-simple - A friendly effect system for Haskell

conduit-combinators - Type classes for mapping, folding, and traversing monomorphic containers

effect-monad - Provides 'graded monads' and 'parameterised monads' to Haskell, enabling fine-grained reasoning about effects.

rank2classes - Grammatical parsers - combinator library for parsing general context-free grammars