Add Github workflows

Author: sdiehl

.github/workflows/cabal.yml

@@ -0,0 +1,49 @@
+name: Cabal CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  build:
+    name: cabal ${{ matrix.ghc }}
+    runs-on: ubuntu-16.04
+    strategy:
+      matrix:
+        ghc: ["8.8.1", "8.6.5", "8.6.4", "8.6.3", "8.6.2"]
+        cabal: ["3.0"]
+
+    steps:
+    - uses: actions/checkout@v1
+    - uses: actions/setup-haskell@v1
+      name: Setup Haskell
+      with:
+        ghc-version: ${{ matrix.ghc }}
+        cabal-version: ${{ matrix.cabal }}
+
+    - uses: actions/cache@v1
+      name: Cache ~/.cabal/packages
+      with:
+        path: ~/.cabal/packages
+        key: cabal-packages-${{ matrix.ghc }}
+
+    - uses: actions/cache@v1
+      name: Cache ~/.cabal/store
+      with:
+        path: ~/.cabal/store
+        key: cabal-store-${{ matrix.ghc }}
+
+    - uses: actions/cache@v1
+      name: Cache dist-newstyle
+      with:
+        path: dist-newstyle
+        key: dist-newstyle-${{ matrix.ghc }}
+
+    - name: Install dependencies
+      run: |
+        cabal update
+    - name: Build
+      run: |
+        cabal new-build

.github/workflows/stack.yml

@@ -0,0 +1,65 @@
+name: Stack CI
+
+on:
+  push:
+  pull_request:
+  schedule:
+  - cron: "0 0 * * 1"
+
+jobs:
+  build:
+    name: stack ${{ matrix.plan.resolver }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macOS-latest]
+        plan:
+        - { build: stack, resolver: "lts-13"  }   # redundant because lts-14 checks ghc-8.6 already
+        - { build: stack, resolver: "lts-14"  }   # ghc-8.6.5
+        #- { build: stack, resolver: "nightly" }
+        include: []
+        exclude:
+        - os: macOS-latest
+          plan:
+            build: cabal
+
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Install OS Packages
+      uses: mstksg/get-package@v1
+      with:
+        apt-get: ${{ matrix.apt-get }}
+        brew: ${{ matrix.brew }}
+    - uses: actions/checkout@v1
+
+    - name: Setup stack
+      uses: mstksg/setup-stack@v1
+
+    - uses: actions/cache@v1
+      name: Cache .stack-work
+      with:
+        path: .stack-work
+        key: stack-work
+
+    - uses: actions/cache@v1
+      name: Cache ~/.stack
+      with:
+        path: ~/.stack
+        key: stack
+
+    - name: Install dependencies
+      run: |
+        set -ex
+        stack --no-terminal --install-ghc --resolver $ARGS test --bench --only-dependencies
+        set +ex
+      env:
+        ARGS: ${{ matrix.plan.resolver }}
+        BUILD: ${{ matrix.plan.build }}
+
+    - name: Build
+      run: |
+        set -ex
+        stack --no-terminal --resolver $ARGS test --bench --no-run-benchmarks --haddock --no-haddock-deps
+        set +ex
+      env:
+        ARGS: ${{ matrix.plan.resolver }}
+        BUILD: ${{ matrix.plan.build }}