Adding haskell.nix based default and shell.nix (#141)

Co-authored-by: Ben Ford <ben@perurbis.com>

.github/workflows/ci.yml

@@ -0,0 +1,18 @@
+name: "Nix CI"
+on:
+  pull_request:
+  push:
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2.3.1
+    - uses: cachix/install-nix-action@v10
+      with:
+        skip_adding_nixpkgs_channel: true
+    - uses: cachix/cachix-action@v6
+      with:
+        name: cdodev
+        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
+    - run: cachix use iohk && cachix use cdodev
+    - run: nix-build

README.md

@@ -79,6 +79,9 @@ $ stack ./examples/doc_drawCircle.hs
 This should render the `doc_drawCircle` example in a new browser window. If you then change the
 animation source code, the browser window will automatically reload and show the updated animation.
 
+
+## Using Cabal
+
 It's also possible to use cabal instead of stack:
 
 ```console
@@ -86,10 +89,34 @@ $ git clone https://github.com/reanimate/reanimate.git
 $ cd reanimate/
 $ cabal v2-build
 $ # Workaround for a cabal bug: https://github.com/haskell/cabal/issues/6235
-$ export reanimate_datadir=`pwd` 
+$ export reanimate_datadir=`pwd`
 $ cabal v2-exec -- runhaskell examples/doc_drawCircle.hs --ghc ghc
 ```
 
+## Using Nix
+
+If you'd rather use nix to build an environment with all of the system dependencies mentioned previously do:
+
+```console
+$ git clone https://github.com/reanimate/reanimate.git
+$ cd reanimate/
+$ nix-shell
+[nix-shell:./reanimate]$ cabal v2-build --write-ghc-environment-files=always
+```
+
+If you have cachix available run `cachix use cdodev` before you drop into the nix shell. This will significantly speed things up!
+
+This will write a file in the working directory like
+`.ghc.environment.x86_64-linux-8.8.3` which will enable commands like `runhaskell`
+to pick up reanimate.
+
+Now, still within the `nix-shell` you can run:
+
+```console
+[nix-shell:./reanimate]$ reanimate_datadir=. runhaskell examples/doc_drawCircle.hs --ghc `which ghc`
+```
+
+
 # Documentation
 
  * API reference: https://hackage.haskell.org/package/reanimate/docs/Reanimate.html

default.nix

@@ -0,0 +1,52 @@
+let
+  haskellNixSrc = fetchTarball {
+    url = "https://github.com/input-output-hk/haskell.nix/tarball/403b1a1b848295b907f4ceaeb0b6508c3f97e3a3";
+    sha256 = "1m32hz6zalfhywrzjir4gn81xbwp9vmxqgv3x746gb1zzmjqdhhs";
+  };
+  # haskellSrcMaster = builtins.fetchTarball https://github.com/input-output-hk/haskell.nix/archive/master.tar.gz;
+  haskellNix = import haskellNixSrc {};
+
+  all-hies = fetchTarball {
+    # Insert the desired all-hies commit here
+    url = "https://github.com/infinisil/all-hies/tarball/534ac517b386821b787d1edbd855b9966d0c0775";
+    # Insert the correct hash after the first evaluation
+    sha256 = "0bw1llpwxbh1dnrnbxkj2l0j58s523hjivszf827c3az5i4py1i2";
+  };
+
+  pkgs = import haskellNix.sources.nixpkgs-2003 (haskellNix.nixpkgsArgs // {
+    overlays = haskellNix.nixpkgsArgs.overlays ++ [
+      (import all-hies {}).overlay
+    ];
+  });
+
+  set = pkgs.haskell-nix.stackProject {
+    name = "reanimate";
+    compiler-nix-name = "ghc883";
+    src = pkgs.haskell-nix.haskellLib.cleanGit {
+      name = "reanimate";
+      src = ./.;
+    };
+  };
+in set.reanimate.components.library // {
+  env = set.shellFor {
+    packages = p: [ p.reanimate ];
+    # exactDeps = true;
+    nativeBuildInputs = [ pkgs.stack
+                          pkgs.zlib.dev
+                          pkgs.zlib.out
+                          pkgs.gmp
+                          pkgs.gnome3.librsvg
+                          pkgs.blender
+                          pkgs.povray
+                          pkgs.ffmpeg
+                          pkgs.texlive.combined.scheme-full
+                        ];
+    tools = {
+      cabal = "3.2.0.0";
+      hie = "unstable";
+    };
+    shellHook = ''
+      export HIE_HOOGLE_DATABASE=$(realpath "$(dirname "$(realpath "$(which hoogle)")")/../share/doc/hoogle/default.hoo")
+    '';
+  };
+}

examples/demo_stars.hs

@@ -1,5 +1,12 @@
-#!/usr/bin/env stack
--- stack runghc --package reanimate
+#!/usr/bin/env cabal
+{- cabal:
+build-depends: base
+            , reanimate
+            , reanimate-svg
+            , vector
+            , random
+            , JuicyPixels
+-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ParallelListComp #-}
 module Main

examples/doc_drawCircle.hs

@@ -1,5 +1,9 @@
-#!/usr/bin/env stack
--- stack runghc --package reanimate
+#!/usr/bin/env cabal
+{- cabal:
+build-depends: base
+            , reanimate
+            , reanimate-svg
+-}
 module Main(main) where
 
 import Reanimate

examples/tut_glue_keyframe.hs

@@ -1,5 +1,10 @@
-#!/usr/bin/env stack
--- stack runghc --package reanimate
+#!/usr/bin/env cabal
+{- cabal:
+build-depends: base
+            , reanimate
+            , reanimate-svg
+            , JuicyPixels
+-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecursiveDo       #-}
 module Main (main) where

shell.nix

@@ -0,0 +1 @@
+(import ./.).env