Add CI

.github/workflows/haskell-ci.yaml

@@ -0,0 +1,75 @@
+name: Build
+on:
+  - push
+  - pull_request
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  main:
+    name: GHC ${{ matrix.ghc }} on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest]
+        ghc:
+          - "9.2.7"
+          - "9.4.5"
+          - "9.6.1"
+        include:
+          - os: macOS-latest
+            ghc: "9.6.1"
+          - os: windows-latest
+            ghc: "9.6.1"
+    steps:
+    - uses: actions/checkout@v3
+    - uses: haskell/actions/setup@v2.3.7
+      id: setup-haskell-cabal
+      with:
+        ghc-version: ${{ matrix.ghc }}
+        cabal-version: "latest"
+        cabal-update: true
+    - uses: actions/cache@v3
+      name: Cache cabal stuff
+      with:
+        path: |
+          ${{ steps.setup-haskell-cabal.outputs.cabal-store }}
+          dist-newstyle
+        key: ${{ runner.os }}-${{ matrix.ghc }}
+
+    - name: Cabal version
+      run: |
+        cabal --version
+
+    - name: Install doctest
+      run: |
+        mkdir -p "${{github.workspace}}/doctest-bin"
+        cabal install --install-method=symlink --installdir "${{github.workspace}}/doctest-bin" doctest
+
+    - name: Unpack
+      run: |
+        cabal sdist --ignore-project --output-directory .
+        cabal get prettyprinter-combinators-*.tar.gz
+
+    - name: Build
+      run: |
+        cd prettyprinter-combinators-*/
+        cabal build all --enable-tests --enable-benchmarks
+
+    - name: Doctest
+      run: |
+        cd prettyprinter-combinators-*/
+        cabal repl --with-ghc "${{github.workspace}}/doctest-bin/doctest" --repl-options=-Wno-missing-export-lists 'lib:prettyprinter-combinators'
+
+    - name: Haddock
+      run: |
+        cd prettyprinter-combinators-*/
+        cabal haddock all
+
+    - name: Cabal check
+      run: |
+        cd prettyprinter-combinators-*/
+        cabal check