# Question about relationship of Cabal and Stack

**URL:** <https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155>\
**Category:** Learn\
**Created:** [March 26, 2020, 5:28pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155 "2020-03-26T17:28:07Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![mhneifer](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/mhneifer/32/488_2.png) [@mhneifer](https://discourse.haskell.org/u/mhneifer)\
**Post date:** [March 26, 2020, 5:28pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/1 "2020-03-26T17:28:08Z")

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I’m just getting started with Haskell and got interested in the available Haskell tool chains. I have done development with Java before and my first thought was that Cabal is like Apache Maven. But then I found Stack and now I wonder what is the relationship between Cabal and Stack. When does one use Cabal and when Stack?

Thanks in advance.

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**Author:** ![belka](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@belka](https://discourse.haskell.org/u/belka)\
**Post date:** [March 26, 2020, 8:44pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/2 "2020-03-26T20:44:15Z")

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Use stack 🙂

There are actually **Cabal** , the library and package format; and **cabal-install** , the package manager. Both, Stack and cabal-install, use Cabal, the library.  
For cabal-install you have to wrte `.cabal` files yourself; Stack has a friendlier package format and generates `.cabal` files (similar to cmake and make or meson and ninja).  
Stack provides more project management features, reproducible builds.

Here is a similar question with more information: [haskell - What is the difference between Cabal and Stack? - Stack Overflow](https://stackoverflow.com/a/42601219/2737998).

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**Author:** ![hvr](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/hvr/32/21_2.png) [@hvr](https://discourse.haskell.org/u/hvr)\
**Post date:** [March 26, 2020, 9:07pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/3 "2020-03-26T21:07:18Z")

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> [@belka](#):
>
> Stack has a friendlier package format and generates `.cabal` files (similar to cmake and make or meson and ninja).  
> Stack provides more project management features, reproducible builds.

Quite frankly this is a strange claim; in what way is the native `.cabal` format unfriendly? In fact, if anything I’d recommend against Stack’s “friendly” format; see e.g. [[Haskell-community] Standard package file format](https://mail.haskell.org/pipermail/haskell-community/2016-September/000262.html)

As for reproducible builds, this is not exclusive to Stack; it may surprise people, but Cabal supported “reproducible builds” since around Cabal 1.18 (released in 2013); it’s something you tend to need when you use Haskell professionally; and if you want to extend the reproducibility beyond the Haskell layer, augmenting Cabal with NixOS is currently the most principled solution I know of.

Moreover, I’d like to offer a more comprehensive answer to OP (taken from [cabal.rst · GitHub](https://gist.github.com/merijn/8152d561fb8b011f9313c48d876ceb07)):

* * *

# The Cabal/Stack Disambiguation Guide

One of the most frequently asked Haskell beginner questions in recent  
years is:

> “Stack or cabal?”

I will helpfully **not** answer this question. Instead I will hope to  
eliminate the confusion that many of the askers seem to have about the  
various different things named “cabal” and how they relate to each other  
and stack.

So, how many things named “cabal” do we have? We have:

1. CABAL (the spec)

2. `.cabal` (the file format)

3. Cabal (the library)

4. `cabal` (the executable)

## How does Stack relate to all this CABAL stuff?

Stack is a replacement for `cabal-install`, i.e. the `cabal` executable.  
The `stack` commandline tool, like `cabal-install` is a tool that uses  
Cabal (the library) to resolve dependencies and build packages. The main  
difference between `cabal-install` and `stack` is how they resolve  
dependencies.

So, what do `cabal-install` and `stack` do differently?

`cabal-install` looks at the declared version ranges of a package in the  
`.cabal` file and using the available versions on Hackage it computes a  
build plan satisfying the version constraints, then compiles using this  
build plan.

`stack` on the other hand uses “resolvers”. A resolver is a snapshot of  
various package versions on Stackage and dependencies are resolved by  
“just use the exact version specified by the resolver”.

It is possible to make `stack` resolve things dynamically\[1\] as  
`cabal-install` and vice versa, you can create snapshots (freeze files)  
using `cabal-install` to accomplish what `stack` does.

## So which tool should I use?

Honestly, at this point I don’t think there is much difference, use  
whichever tool best fits your workflow. The only real strong opinion I  
have is that you should avoid Stack’s (optional) use of `hpack` at all  
costs.

`hpack` is a tool that generates `.cabal` files from `package.yaml`. In  
the past there were some (in my personal opinion, weak) reasons for  
using `package.yaml`, but those are nowadays possible in `.cabal` too.

`package.yaml` does not support all CABAL features and requires all your  
potential users to install extra tooling. The `.cabal` format is  
understood by both `cabal-install` and `stack` without extra tools, so  
everyone can just use/contribute with their preferred tools.

* * *

1. As of Stack 2.x this functionality has been dropped from Stack and  
so this is no longer possible.

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**Author:** ![gilmi](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/gilmi/32/45_2.png) [@gilmi](https://discourse.haskell.org/u/gilmi)\
**Post date:** [March 26, 2020, 9:59pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/4 "2020-03-26T21:59:25Z")

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I think the post hvr linked is good. I’d like to share another one that I like about the differences between the two: [https://sigkill.dk/blog/2019-10-17-haskell-build-systems-for-non-haskellers.html](https://sigkill.dk/blog/2019-10-17-haskell-build-systems-for-non-haskellers.html)

And also share an article that describes how to use each tool: [https://kowainik.github.io/posts/2018-06-21-haskell-build-tools.html](https://kowainik.github.io/posts/2018-06-21-haskell-build-tools.html)

Have fun!

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<div class="post-metadata">

**Author:** ![mhneifer](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/mhneifer/32/488_2.png) [@mhneifer](https://discourse.haskell.org/u/mhneifer)\
**Post date:** [March 27, 2020, 11:09am UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/5 "2020-03-27T11:09:31Z")

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I’m sorry for asking FAQ. Will read more documentation first

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**Author:** ![epicallan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/epicallan/32/266_2.png) [@epicallan](https://discourse.haskell.org/u/epicallan)\
**Post date:** [March 28, 2020, 9:34am UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/6 "2020-03-28T09:34:41Z")

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Don’t be sorry for asking an FAQ, its a sign that we as a community need to do more to make the information you seek more accessible. Please keep asking.

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**Author:** ![BebeSparkelSparkel](https://avatars.discourse-cdn.com/v4/letter/b/278dde/32.png) [@BebeSparkelSparkel](https://discourse.haskell.org/u/BebeSparkelSparkel)\
**Post date:** [April 4, 2020, 1:22pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/7 "2020-04-04T13:22:08Z")

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> [@hvr](#):
>
> `hpack` is a tool that generates `.cabal` files from `package.yaml` . In  
> the past there were some (in my personal opinion, weak) reasons for  
> using `package.yaml` , but those are nowadays possible in `.cabal` too.

How do you get the .cabal file to dynamically export modules? In projects, I create a lot of new modules and do not like modifying the cabal file to export those each time when hpack does it for me.

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**Author:** ![mhneifer](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/mhneifer/32/488_2.png) [@mhneifer](https://discourse.haskell.org/u/mhneifer)\
**Post date:** [April 25, 2020, 6:14pm UTC](https://discourse.haskell.org/t/question-about-relationship-of-cabal-and-stack/1155/8 "2020-04-25T18:14:23Z")

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Just for the files, here’s the official Stack FAQ entry that answers my question.

[What is the relationship between stack and cabal?](https://docs.haskellstack.org/en/stable/faq/#what-is-the-relationship-between-stack-and-cabal)

Thanks for all the replies.