GitHub Actions CI (haskell-nix#12)

Similar to Gabriella439/nix-diff#37

.github/workflows/ci.yaml

@@ -0,0 +1,38 @@
+jobs:
+  build:
+    runs-on: ubuntu-18.04
+    steps:
+      - uses: "actions/checkout@v1"
+      - id: setup-haskell-cabal
+        uses: "haskell/actions/[email protected]"
+        with:
+          cabal-version: "${{ matrix.cabal }}"
+          enable-stack: false
+          ghc-version: "${{ matrix.ghc }}"
+      - uses: "actions/cache@v1"
+        with:
+          key: "${{ runner.os }}-${{ matrix.ghc }}-cabal"
+          path: "${{ steps.setup-haskell-cabal.outputs.cabal-store }}"
+      - name: Install dependencies
+        run: |
+          cabal update
+          cabal build --enable-tests --enable-benchmarks --only-dependencies
+      - name: build
+        run: cabal build --enable-tests --enable-benchmarks
+      - name: test
+        run: cabal test --enable-tests
+      - name: haddock
+        run: cabal haddock 
+    strategy:
+      matrix:
+        cabal:
+          - '3.2'
+        ghc:
+          - '8.10.4'
+          - '8.8.4'
+          - '8.6.5'
+          - '9.0.1'
+name: Haskell CI
+on:
+  - push
+  - pull_request

ci.dhall

@@ -0,0 +1,16 @@
+let haskellCi =
+      https://raw.githubusercontent.com/sorki/github-actions-dhall/pending/haskell-ci.dhall
+
+in    haskellCi.generalCi
+        haskellCi.matrixSteps
+        ( Some
+            { ghc =
+              [ haskellCi.GHC.GHC8104
+              , haskellCi.GHC.GHC884
+              , haskellCi.GHC.GHC865
+              , haskellCi.GHC.GHC901
+              ]
+            , cabal = [ haskellCi.Cabal.Cabal32 ]
+            }
+        )
+    : haskellCi.CI.Type

ci.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Script by @fisx
+
+set -eo pipefail
+cd "$( dirname "${BASH_SOURCE[0]}" )"
+
+echo "regenerating .github/workflows/ci.yaml..."
+
+# based on https://github.com/vmchale/github-actions-dhall
+which dhall-to-yaml || cabal install dhall-yaml
+dhall-to-yaml --file ci.dhall > .github/workflows/ci.yaml