cats VS Ammonite-Ops

Compare cats vs Ammonite-Ops and see what are their differences.


Lightweight, modular, and extensible library for functional programming. (by typelevel)


Scala Scripting (by lihaoyi)
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cats Ammonite-Ops
24 10
4,705 2,496
0.6% 0.5%
9.7 8.0
about 5 hours ago 17 days ago
Scala Scala
GNU General Public License v3.0 or later 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.


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 2022-06-02.


Posts with mentions or reviews of Ammonite-Ops. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2022-02-01.
  • Scala 3 Reflection
    5 projects | | 1 Feb 2022
    Scripting API is quite limited, so the third option. - reuse the ammonite scripts or look how this is implemented (using internal compiler API),
  • New to Scala
    1 project | | 14 Oct 2021
    Your exposure to Functional Programming with Haskell and Clojure suggest you will certainly pick up Scala quickly. With ZIO and cats, you can write robust software quickly. Consider the excellent Coursera Scala course. Get "the Red Book", and most important, play. Experiment to see how things work. Get
  • Audacity Fork Without Any Sentry Telemetry or Crash Reporting
    9 projects | | 5 Jul 2021
    Here's an example of a smaller project that added telemetry without suffering a fork:

  • Scripting with Java – Improving Approachability
    2 projects | | 12 May 2021
    Or ammonite - I've ran Gatling performance test from a simple script based on this gist it fetches all the dependencies, compiles and runs the test, producing nice html report..
  • 25 years of OCaml
    3 projects | | 10 May 2021
    Scala with the Typelevel ecosystem. Stay on the jVM, but have a much more pleasant and robust experience, including a great REPL.
  • The Scala ecosystem and circular dependencies?
    3 projects | | 10 Apr 2021
    If you are installing, and you are learning, I would also recommend ammonite as an easier REPL.
  • IPython as a System Shell
    3 projects | | 6 Apr 2021
    I've been using amm on and off

    pretty nice if you know scala, still have to use regular shell(s) so I do not forget them

  • Ammonite: Scala Scripting
    1 project | | 12 Mar 2021
  • A Lisp REPL as my main shell
    5 projects | | 8 Feb 2021
    I've never tested Ammonite, only read the, so I'm only guessing here.

    From what I understand, Ammonite was designed as a "readline shell" as I wrote in the article. It perpetuates this approach that everything is a command.

    The thesis of my article suggests we do the opposite: I'm suggesting to rethink shells by starting from the interface (here the SLY REPL) and then implement the shell features.

    In particular, it seems that Ammonite does not support back-references and I'm not sure it has an interactive inspector.

    While Ammonite seems to be a definite improvement over the _syntax_ of Bash, etc., I'm not sure it brings much novelty in terms of user interface. But again, I know very little about it so I may have missed some features :)

    5 projects | | 8 Feb 2021
    I wonder what people think about Ammonite (

    It's not Lisp but Scala so may not be the authors language of choice however it can be used as a Shell:

    I am personally using it and compared to a classical shell like Bash it's really nice for more structured data related tasks (exploring some API, checking some data, creating a bunch of PRs at once, ...).

    It also makes use of Scala's adjustable syntax and functional concepts so you basically get shell piping but in a strongly typed fashion (e.g.

What are some alternatives?

When comparing cats and Ammonite-Ops you can also consider the following projects:

Shapeless - Generic programming for Scala

Scalaz - Principled Functional Programming in Scala

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

better-files - Simple, safe and intuitive Scala I/O

Scala Async - An asynchronous programming facility for Scala

Monocle - Optics library for Scala

ScalaTest - A testing tool for Scala and Java developers

calculator - Windows Calculator: A simple yet powerful calculator that ships with Windows

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.

Scala-Logging - Convenient and performant logging library for Scala wrapping SLF4J.