Shell.nix for "Parallel and Concurrent Programming in Haskell" by Simon Marlow

1

Hello,

I’ve made this shell.nix that allows for me to reliably build the packages and follow along with the book using cabal.

# shell.nix
{ nixpkgs ? import (builtins.fetchTarball {
                      url = "https://github.com/NixOS/nixpkgs/archive/5c79b3dda06744a55869cae2cba6873fbbd64394.tar.gz"; 
# Pins to a version of nixpkgs where ghc 8.8.4 was the main ghc (I think)
# gotten from https://lazamar.co.uk/nix-versions/?package=ghc&version=8.8.4&fullName=ghc-8.8.4&keyName=ghc&revision=5c79b3dda06744a55869cae2cba6873fbbd64394&channel=nixpkgs-unstable#instructions
                      }) {}, 
                    }:


let 
  hpkgs = nixpkgs.haskell.packages."ghc884";

in 
  hpkgs.shellFor {
    name = "parconc-examples";
    packages = _: [];
    buildInputs = with hpkgs; [ 
      cabal-install
      haskell-language-server
      nixpkgs.pkg-config # Needed to build some packages
      nixpkgs.zlib # Needed to build some packages
      implicit-hie
  ];
}
  1. Enter the environment with nix-shell.
  2. Update cabal with cabal update.
  3. Build the executable(s) with cabal build [package]
  4. Run the executable with cabal run. So for example:
$ ghc -O2 rpar.hs -threaded
$ ./rpar 1 + RTS -N2

becomes

$ cabal build rpar
$ cabal run rpar 1 -- +RTS -N2

EDIT: Got HLS working.

Added implicit-hie to buildInputs.

OPTIONAL: To work with HLS, in the nix-shell, run gen-hie > hie.yaml

3 Likes