Rework Nix infrascture & CI

.github/workflows/ci.yml

@@ -16,14 +16,13 @@ jobs:
   nix:
     name: nix build
     runs-on: ubuntu-latest
-    container:
-      image: 'nixos/nix:2.3.6'
     steps:
       - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v31
 
       - name: Build
         run: |
-          nix-build
+          nix build
 
   cabal:
     name: ${{ matrix.os }} / ghc ${{ matrix.ghc }}
@@ -45,7 +44,6 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-      #      if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/master'
 
     - uses: haskell-actions/setup@v2
       id: setup-haskell-cabal
@@ -54,19 +52,12 @@ jobs:
         ghc-version: ${{ matrix.ghc }}
         cabal-version: ${{ matrix.cabal }}
 
-      # This can be dropped once
-      # https://github.com/clash-lang/clash-compiler/pull/2790 is merged.
-    - name: Apply GHC-9.10 cabal project configuration
-      if: matrix.ghc == "9.10.1"
-      run: |
-        mv cabal.ghc-9.10.project cabal.project
-
     - name: Freeze
       run: |
         cabal update
         cabal freeze
 
-    - uses: actions/cache@v1
+    - uses: actions/cache@v4
       name: Cache ~/.cabal/store
       with:
         path: ${{ steps.setup-haskell-cabal.outputs.cabal-store }}

flake.nix

@@ -0,0 +1,52 @@
+{ 
+  description = "A flake for developing & using circuit-notation";
+  inputs = {
+    clash-compiler.url = "github:clash-lang/clash-compiler";
+  };
+  outputs = { self, flake-utils, clash-compiler, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        # What version of the GHC compiler to use
+        compiler-version = "ghc910";
+
+        pkgs = (import clash-compiler.inputs.nixpkgs {
+          inherit system;
+        }).extend clash-compiler.overlays.${compiler-version};
+        clash-pkgs = pkgs."clashPackages-${compiler-version}";
+
+        overlay = final: prev: {
+          circuit-notation = prev.developPackage {
+            root = ./.;
+            overrides = _: _: final;
+          };
+        };
+
+        hs-pkgs = clash-pkgs.extend overlay;
+      in
+      {
+        # Expose the overlay which adds circuit-notation
+        # The base of the overlay is clash-pkgs
+        overlay = overlay;
+
+        devShells.default = hs-pkgs.shellFor {
+          packages = p: [
+            p.circuit-notation
+          ];
+
+          nativeBuildInputs = 
+            [
+              # Haskell stuff
+              hs-pkgs.cabal-install
+              hs-pkgs.cabal-plan
+              hs-pkgs.haskell-language-server
+              hs-pkgs.fourmolu
+            ]
+          ;
+        };
+        packages = {
+          circuit-notation = hs-pkgs.circuit-notation;
+
+          default = hs-pkgs.circuit-notation;
+        };
+      });
+}