Reflex Workshop

Development shell - Nix / NixOS

Nix

Add something like this to your nix.conf:

substituters = https://cache.nixos.org/ https://nixcache.reflex-frp.org
trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ryantrinkle.com-1:JJiAKaRv9mWgpVAz8dwewnZe0AzzEAzPkagE9SP5NWI=

NixOS

You'll want to add the reflex cache to /etc/nix/configuration.nix:

  nix.binaryCaches = [
    "https://nixcache.reflex-frp.org"
  ];
  nix.binaryCachePublicKeys = [
    "ryantrinkle.com-1:JJiAKaRv9mWgpVAz8dwewnZe0AzzEAzPkagE9SP5NWI="
  ];

and then rebuild with nixos-rebuild switch.

Shell

After that you'll want to run the ./dev.sh and hoogle server -p 9090 --local commands from a nix-shell:

cd ~/reflex-workshop
nix-shell

VirtualBox Appliance

vm.nix is a nix expression that builds a VirtualBox appliance. Now that the QFPL Hydra no longer exists, you will have to build it yourself if you want it.

nix build -f vm.nix will build the appliance, but be warned: it will take a while and peak at about 25GiB of disk usage. If you have a tmpfs mounted on /tmp, you will run out of space. I usually do something like this:

  # On a multi-user nix install, build commands are passed
  # through the nix daemon. We switch to root to avoid this.
  # On a single-user nix install, working as root is probably
  # not necessary.
$ sudo -i

# mkdir /vmtmp

  # --no-link stops the creation of a `result` symlink owned by root.
# TMPDIR=/vmtmp nix build -f /path/to/vm.nix --no-link -L

# rmdir /vmtmp

  # As your normal user, re-run the build (which will be quick), to get
  # the link to the .ova from the nix store:
$ nix build -f /path/to/vm.nix

Getting set up

• Download and install VirtualBox
• Import the OVA into VirtualBox
  • The menu option should be something like: File > Import Appliance

Editors and tools

The VirtualBox appliance comes with these text editors

• emacs
• gedit
• vim and these Haskell tools:
• cabal-install
• ghcid
• ghc-mod
• hasktags
• hindent
• hlint
• hoogle
• stylish-haskell

If you want to configure vim or emacs to your liking before the workshop, go for it.

Running the workshop

The workshop is run from within the VM

• Open a terminal

  • Run the workshop code under ghcid

    cd reflex-workshop
    ./dev.sh
    

• Open Chromium

  • Visit http://localhost:8080 for the workshop
  • Visit http://localhost:9090 for a local Hoogle instance