haskell.nix examples

This repository serves as an example of haskell.nix usage. It's kept to the very basic minimum on purpose. The idea is to ensure that we do not conflate complex project setups with the core of haskell.nix.

Objectives

The objective of haskell.nix is to simplify the building of Haskell packages by minimizing the need for customization. It achieves this through the use of Import From Derivation (IFD) expressions, which allow for dynamic adaptation to Haskell projects without modifying the Nix code. While IFDs may have performance drawbacks and are not allowed in nixpkgs, they provide flexibility in the context of haskell.nix.

The flake.nix has been kept intentionally simple, with as little abstraction as possible. While this leads to a more verbose flake.nix, our hope is that it makes it much easer to read and follow along.

Build Targets

Running nix flake show --all-systems --option allow-import-from-derivation true will yield:

git+file:///.../haskell-nix-example
├───defaultPackage
│   ├───aarch64-darwin: package 'hello-exe-hello-1.0.0.2'
│   ├───aarch64-linux: package 'hello-exe-hello-1.0.0.2'
│   ├───x86_64-darwin: package 'hello-exe-hello-1.0.0.2'
│   └───x86_64-linux: package 'hello-exe-hello-1.0.0.2'
└───packages
    ├───aarch64-darwin
    │   └───hello: package 'hello-exe-hello-1.0.0.2'
    ├───aarch64-linux
    │   └───hello: package 'hello-exe-hello-1.0.0.2'
    ├───x86_64-darwin
    │   └───hello: package 'hello-exe-hello-1.0.0.2'
    └───x86_64-linux
        ├───hello: package 'hello-exe-hello-1.0.0.2'
        ├───hello-dynamic: package 'hello-exe-hello-aarch64-unknown-linux-gnu-1.0.0.2'
        ├───hello-javascript: package 'hello-exe-hello-1.0.0.2'
        ├───hello-mingw: package 'hello-exe-hello-x86_64-w64-mingw32-1.0.0.2'
        ├───hello-static-musl: package 'hello-exe-hello-aarch64-unknown-linux-musl-1.0.0.2'
        └───hello-ucrt64: package 'hello-exe-hello-x86_64-w64-mingw32-1.0.0.2'

We can then get packages for each cross target as needed.