Update to GHC 9.6, latest Stackage Nightly, and use BNFC in setup

.gitattributes

@@ -0,0 +1,3 @@
+rzk/grammar/Syntax.cf linguist-language=grammar
+rzk/src/Language/Rzk/Syntax/* linguist-generated=true
+docs/** linguist-documentation

.github/workflows/ghc.yml

@@ -0,0 +1,113 @@
+name: GHC (build, test, haddock)
+
+# Controls when the workflow will run
+on:
+  push:
+    branches: [main, develop]
+    tags: [v*]
+    paths:
+      - .github/workflows/ghcjs.yml
+      - rzk/**
+      - stack.yaml
+      - rzk.yaml
+      - "**/*.rzk.md"
+      - "**/*.rzk"
+      - "**/*.rzk.tex"
+  pull_request:
+    branches: [develop]
+    paths:
+      - .github/workflows/ghcjs.yml
+      - rzk/**
+      - stack.yaml
+      - rzk.yaml
+      - "**/*.rzk.md"
+      - "**/*.rzk"
+      - "**/*.rzk.tex"
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: "Build and test with GHC"
+    runs-on: ubuntu-latest
+    outputs:
+      rzkPath: ${{ steps.rzkBinary.outputs.rzkPath }}
+
+    steps:
+      - name: 📥 Checkout repository
+        uses: actions/checkout@v3
+
+      - name: 🧰 Setup Stack
+        uses: freckle/stack-action@v4
+        with:
+          cache-prefix: ${{ runner.os }}-stack-
+
+      - name: 🔨 Build dependencies (with Stack)
+        run: |
+          stack build --only-dependencies
+
+      - name: 🔨 Build and test (with Stack)
+        run: |
+          stack test
+
+      - name: Tar and strip the binary
+        id: rzkBinary
+        run: echo "rzkPath=$(stack exec -- which rzk)" >> "$GITHUB_OUTPUT"
+
+      - name: Upload rzk binary as Artifact
+        uses: actions/upload-artifact@v3
+        with:
+          path: ${{ steps.rzkBinary.outputs.rzkPath }}
+          name: "rzk-${{ github.ref_name }}"
+          if-no-files-found: error
+
+  haddock:
+    needs: [build]
+    if: ${{ github.ref_name == 'develop' }}
+    name: "Build and upload Haddock documentation (develop)"
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: 📥 Checkout repository
+        uses: actions/checkout@v3
+
+      - name: 🧰 Setup Stack
+        uses: freckle/stack-action@v4
+        with:
+          cache-prefix: ${{ runner.os }}-stack-
+
+      - name: 🔨 Build Haddock Documentation (with Stack)
+        run: |
+          stack haddock
+          mkdir -p dist/haddock
+          mv $(stack path --local-doc-root)/* dist/haddock
+
+      - name: 🚀 Publish Haddock Documentation
+        uses: JamesIves/github-pages-deploy-action@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          folder: dist/haddock
+          target-folder: haddock
+          single-commit: true
+
+  rzk:
+    needs: [build]
+    name: "Check Rzk formalizations"
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: 📥 Checkout repository
+        uses: actions/checkout@v3
+
+      - name: 📥 Download rzk
+        uses: actions/download-artifact@v3
+        with:
+          name: ${{ needs.build.outputs.rzkPath }}
+
+      - name: Check Rzk files
+        run: ./rzk typecheck docs/docs/examples/recId.rzk.md # FIXME: rely on rzk.yaml instead
+        shell: bash

.github/workflows/ghcjs.yml

@@ -1,4 +1,4 @@
-name: Build with GHCJS and Deploy to GitHub Pages
+name: GHCJS (build and deploy Rzk playground)
 
 on:
   push:
@@ -10,23 +10,24 @@ on:
       - rzk-js/**
       - rzk-playground/**
       - stack.yaml
-      - '**/*.nix'
+      - "**/*.nix"
   pull_request:
-    branches: [main, develop]
+    branches: [develop]
     paths:
+      - .github/workflows/ghcjs.yml
       - rzk/**
       - rzk-js/**
       - rzk-playground/**
       - stack.yaml
-      - '**/*.nix'
+      - "**/*.nix"
 
   workflow_dispatch: # allow triggering this workflow manually
 
 permissions:
   contents: write
 
 jobs:
-  build-and-deploy:
+  build-and-deploy-with-ghcjs:
     runs-on: ubuntu-latest
     steps:
       - name: 📥 Checkout repository