nix-haskell-template

This is a cookiecutter repository which contains my current Haskell jumping off point. Nix has the concepts of templates but they don't really offer the customizability I am looking for here.

Get the template

To get this cookiecutter,

nix develop nixpkgs#cookiecutter --command cookiecutter gh:chiroptical/nix-haskell-template

You can install cookiecutter via their directions and run,

cookiecutter gh:chiroptical/nix-haskell-template

This will create a directory with the package name you specify in cookiecutter. If you cd into the directory, you'll see a scaffold for a Haskell flake project.

Getting started

You could simply nix develop, but I tend to prefer direnv and nix-direnv. To use these, follow their installation procedures and add a file .envrc with contents:

use flake

If you see something like,

direnv: error /.../.envrc is blocked. Run `direnv allow` to approve its content

Then direnv is set up properly. If not follow the installation instructions. Once you enter direnv allow it will set up your shell with all the packages in package.yaml. If you notice builds are installing a bunch of packages, likely you need to refresh your nix shell via direnv reload. After that completes, you should be in the shell! From there you can run make run which will compile the project and print the package name you specified when running cookiecutter. There are some other make targets, e.g. make format will format your haskell and nix code.

Options

• Define GHC_OPTIONS in your .envrc to pass options to ghc