iron VS cats

Compare iron vs cats and see what are their differences.

cats

Lightweight, modular, and extensible library for functional programming. (by typelevel)
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iron cats
20 43
403 5,153
- 0.8%
8.3 8.9
11 days ago 5 days ago
Scala Scala
Apache License 2.0 GNU General Public License v3.0 or later
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.

iron

Posts with mentions or reviews of iron. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2024-02-02.
  • Make Invalid States Unrepresentable
    2 projects | dev.to | 2 Feb 2024
    Scala has quite good support for refined types across multiple libraries. A solution using the refined library might look something like
  • Y-at-il icy gens que creere son propre project open source?
    2 projects | /r/programmation | 5 Dec 2023
  • Effect of Perceptual Load on Performance Within IDE in People with ADHD Symptoms
    7 projects | news.ycombinator.com | 14 Jul 2023
    > The output you see is not generated by python.

    Obviously, as running the code generates a very different output…

    > It's generated by an external type checker.

    I know.

    But again, you didn't say that.

    You said the above code "generates" this…

    Maybe you've heard that by now somewhere: Words matter… ;-)

    > The context is python. We're talking about python. I'm making a statement about python.

    No, you made a statement about type checking. Here the full quote once again:

    > The contents of a string can't be type checked and if all methods are defined this way on a class none of it can be checked.

    Nothing in this statement is about Python.

    All I did was just proving your words once again to be nonsense: You can statically dispatch (which involves static type checking!) just fine on strings. My (Scala) code is prove of this fact.

    > There is literally nothing in my statement to indicate I'm making a general statement about type checking.

    LOL. Do you actually know what you're writing? Once more:

    > The contents of a string can't be type checked and if all methods are defined this way on a class none of it can be checked.

    That's a general statement… It couldn't be even more general, actually.

    > But I will say checking for the contents of a string is rare for a type checker to do. That is a general statement that is generally true.

    Once again complete nonsense.

    There are whole libraries doing more or less nothing else than handling singleton types.

    Whole software layers utilize that! But I guess you never heard of static data validation…

    https://github.com/Iltotore/iron

    You have so little clue, but such a big mouth… That's so embarrassing.

    A helpful tip: Stop spiting out maximally general claims (because these are almost always wrong!), and think about what you're actually writing.

    What's in your fantasy, or what you "may have meant" is irrelevant!

    > The guy made factually incorrect statements and so did you.

    That's exactly what I'm talking about: You're a severe DK victim as it seems…

    > It's just true that he's wrong.

    No, actually you are wrong with almost every claim, like I've proven now several times. And this nonsense still didn't stop… Oh, boy!

    > people shouldn't get worked up about someone else identifying a mistake.

    Think about that once again. Especially in the context that it's you who is wrong here with almost everything you say.

    And no, nobody is "pedantic". It only gets quite unrealistic that someone who doesn't even get banal prose straight would be able to write any code. Because the computer is actually very pedantic. And after production is on fire you can't just come to your boss and excuse yourself with "but I've meant this differently, just the stupid computer did again not understand what I've meant".

    But to be honest this would actually explain:

    > I've likely worked for more companies then you in the last 5 years or so due to my personality. I don't stay at one place for long.

    I have some suspicions to why you don't stay anywhere for long… And yes, that would be indeed related to personality…

  • Does the fthomas/refined library work differently in Scala 3?
    3 projects | /r/scala | 20 Jun 2023
    You might want to check out Iron.
  • Iron updates: turning opaque types into value objects
    2 projects | /r/scala | 6 Jun 2023
    And there is a beginner-friendly ticket: Add alias for True constraint and IronType[A, True]
  • Iron v2.1.0 is out!
    2 projects | /r/scala | 15 Apr 2023
    Check the Github page for more information.
    2 projects | /r/scala | 15 Apr 2023
  • Design by contract - Preconditions and Postconditions - I'm really amazed with Scala.
    4 projects | /r/scala | 2 Mar 2023
    Scala likes to do design-by-contract on the type level. You encode your pre- and post- conditions into types. Libraries like iron (scala 3) https://github.com/Iltotore/iron and refined (scala 2) https://github.com/fthomas/refined allow you to do all that without throwing any exceptions and they can even enforce some simple predicates at compile time.
    4 projects | /r/scala | 2 Mar 2023
  • Restrict uses of annotation in Scala
    2 projects | /r/scala | 20 Feb 2023
    Annotation is not the only way (and probably not the best IMHO) to do refined types. You might be interested in Iron in Scala 3 or Refined in Scala 2/3.

cats

Posts with mentions or reviews of cats. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-07-05.
  • Beware of teammates who refactor code based on personal taste without proper documentation or completeness. Sounds familiar.
    2 projects | /r/programming | 5 Jul 2023
    A functional programming library: https://typelevel.org/cats/
  • Is Scala worth learning in 2023?
    5 projects | /r/scala | 29 Jun 2023
    Learn something that pays the bill first - nowadays it's Golang/Rust react/typescript. Then you can try some pure fp libs like fp-ts and fp-core.rs, and look through existing scala cats docs. If you'll feel bad about it - that's totally fine and expectable, fp takes a paradigm shift and not that many dev able to shift their brains way of thought due to basic psychological rigidity) (inability to change habits and to modify concepts/attitudes once developed). And that's purely a staffing and management issue - folks hired randoms out of the blue, and called 'em a team.
  • Going into year 2 of Software Development Foundation Degree, have a particular liking for OOP and SQL, any tips, info or pointers on where to go from there?
    2 projects | /r/cscareerquestions | 29 May 2023
    I'm sorry, but have you ever done functional programming for a real company, like in a functional programming language like Haskell, Scala, or F#? Have you ever used Scala cats or scalaz? Have you ever learned category theory and how to apply its abstractions in software? Listen u/judethedude2106 this person hasn't gone as far down the functional programming rabbit hole as I have. Beyond learning the basics like the difference between pure and impure functions, what are closures, what higher order functions are and the most common ones like .map, .filter, and .flatmap, the immutable collections like immutable linked lists and trees, and what a Monad is and common monads like those used for futures/promises, async programming, and Option (Some or None, which is used instead of null checking), the more advanced functional programming stuff like category theory based abstractions are totally useless for real jobs and is just a giant time suck. Don't waste years on functional programming, spend at most a few months on it and no more.
  • rsmonad: Monads in stable Rust (+ Applicative, Alternative, Functor, Monoid, ...)
    2 projects | /r/rust | 24 May 2023
    As a former functional programmer in Scala, please do not go deep into the Category Theory programming. Scala has libraries like this one called "Cats", a cute shortened name for "Category Theory", but code that makes heavy use of these constructs is not understandable to other programmers. Other than using Monads as a design pattern for things like Options (which can be "Some" or "None"), Futures or Promises (which is used for asynchronous programming), and a few other things, please do not make heavy use of category theory constructs in real programming projects that will have other developers working on them. It is a rabbit hole that may be fun but is not super practical. Sure, write pure functions without side effects, but do not use the words "Bimonad", "Invariant Monoidal", and "Semigroup" in your code. The most common, practical application/use of functional programming is basic things like closures, .map, .filter, maybe chaining maps with like a .flatmap or whatever your programming language uses instead of chain or flatmap, and SQL that uses keywords like WHERE which can be represented in code by using a call to .filter. Like the place where these constructs are used most is in data processing like with SQL, ETL (Extract Transform, Load) jobs, Java's MapReduce on Hadoop, Scala's Apache Spark, and other data processing type things. Haskell is not a popular programming language in real world projects for a number of reasons and one of them is the heavy and sometimes impractical use of Category Theory.
  • Tmux, NeoVim, etc. to write pure Kotlin code?
    2 projects | /r/Kotlin | 30 Apr 2023
    At a previous job of mine we actually had an entirely pure Scala ecosystem using cats which instead uses typeclasses, referential transparency, and other FP concepts as the foundations for how to code. So a lot of flexibility to the language.
  • [E => *] Type
    2 projects | /r/scala | 9 Mar 2023
    Thanks! It's used heavily here
  • for comprehension and some questions
    3 projects | /r/scala | 22 Jan 2023
  • Ask HN: How has functional programming influenced your thinking?
    4 projects | news.ycombinator.com | 16 Jan 2023
    I did work in Scala for a few years. We employed Cats[1], and even a bit of Matryoshka[2] though most of the work I do today is in Python.

    Nowadays I think about computational requirements in terms of relations among behavioral dependencies. Like, "I want to perform operation O on input A and return a B. To do this, I'll need a way to a -> b and a way to b -> b -> b." I often pass these behavioral dependencies in as arguments and it tends to make the inner core of my programs pretty abstract and built up as layers of specificity.

    Zooming out nearly all the way, it makes me feel tethered in a qualitatively unique way to certain deep truths of the universe. In a Platonic sense, invoking certain ideas like a monad make me feel like I'm approaching the divine or at least one instantiation of a timeless universal that operates outside of material existence.

    I'd imagine some mathematicians might see the universe in a similar way - one where immortal relations between ontological forms exist beyond time and space and at the same time can be threaded through the material world by intellectual observation and when those two meet a beautiful collision occurs.

    1. https://typelevel.org/cats/

    2. https://github.com/precog/matryoshka

  • yet another post about type classes in Scala
    2 projects | dev.to | 2 Jan 2023
    Our second type class example attempted to illustrate one last perk: type safety at compile time. It did so with a simplified example of the cats core library for type safety equality comparison between objects. If you're not familiar with cats, go ahead and give it go.
  • Which functional programming language should I learn?
    5 projects | /r/functionalprogramming | 28 Oct 2022
    3) Finally, Scala 3 + cats is a great middle ground. It's a great language to teach and learn FP, even if you learn by yourself, without support from other people. There are lots of materials and even if you get stuck with a concept, you can still implement it using what you knew before.

What are some alternatives?

When comparing iron and cats you can also consider the following projects:

Scalaz - Principled Functional Programming in Scala

Shapeless - Generic programming for Scala

ZIO - ZIO — A type-safe, composable library for async and concurrent programming in Scala

ScalaTest - A testing tool for Scala and Java developers

Monocle - Optics library for Scala

Scala Async - An asynchronous programming facility for Scala

Quicklens - Modify deeply nested case class fields

Scala Graph - Graph for Scala is intended to provide basic graph functionality seamlessly fitting into the Scala Collection Library. Like the well known members of scala.collection, Graph for Scala is an in-memory graph library aiming at editing and traversing graphs, finding cycles etc. in a user-friendly way.

cats-effect - The pure asynchronous runtime for Scala

Hamsters - A mini Scala utility library

Ammonite-Ops - Scala Scripting

scribe - The fastest logging library in the world. Built from scratch in Scala and programmatically configurable.