Implement nix run

.github/workflows/integrate.yaml

@@ -15,42 +15,21 @@ on:
       - "flake.lock"
       - "agora.cabal"
 jobs:
-  # check-formatting:
-  #   runs-on: ubuntu-latest
-  #   steps:
-  #     - uses: actions/checkout@v2.4.0
+  check-formatting:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2.4.0
 
-  #     - uses: actions/cache@v2.1.4
-  #       name: Add Stack files to cache
-  #       with:
-  #         path: ~/.stack
-  #         key: ${{ runner.os }}-stack-formatting
-  #         restore-keys: ${{ runner.os }}-stack-
+      - run: ./.github/format.sh
+        name: Run fourmolu
 
-  #     - run: stack install fourmolu
-  #       name: Install fourmolu
+  run-linter:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2.4.0
 
-  #     - run: ./.github/format.sh
-  #       name: Run fourmolu
-
-  # run-linter:
-  #   runs-on: ubuntu-latest
-  #   steps:
-  #     - uses: actions/checkout@v2.4.0
-
-  #     # - uses: actions/cache@v2.1.4
-  #     #   name: Add Stack files to cache
-  #     #   with:
-  #     #     path: ~/.stack
-  #     #     key: ${{ runner.os }}-stack-lint
-  #     #     restore-keys: ${{ runner.os }}-stack-
-
-  #     # - run: stack install hlint
-  #     #   name: Install hlint
-
-  #     # - run: ~/.local/bin/hlint $(git ls-tree -r HEAD --full-tree --name-only | grep -E '.*\.hs')
-  #     - run: hlint $(git ls-tree -r HEAD --full-tree --name-only | grep -E '.*\.hs')
-  #       name: Run hlint
+      - run: nix run nixpkgs#hlint -- $(git ls-tree -r HEAD --full-tree --name-only | grep -E '.*\.hs')
+        name: Run hlint
 
   check-build:
     runs-on: ubuntu-latest
@@ -79,12 +58,3 @@ jobs:
           key: ${{ runner.os }}-cabal
       - name: Build the project
         run: nix build
-
-      - name: Enter Nix environment
-        run: nix develop
-
-      - run: ./.github/format.sh
-        name: Run fourmolu
-
-      - run: hlint $(git ls-tree -r HEAD --full-tree --name-only | grep -E '.*\.hs')
-        name: Run hlint