Add Github action to test building with GCC and Clang

.github/workflows/gen_matrix.py

@@ -0,0 +1,24 @@
+import json
+import sys
+from pathlib import Path
+
+includes: list[dict[str, str]] = []
+changed_files = json.loads(sys.argv[1])
+for file in changed_files:
+    path = Path(file)
+    print(path)
+
+includes.append({"dir": "2023", "target": "day01"})
+includes.append({"dir": "2023", "target": "day02"})
+includes.append({"dir": "2023", "target": "day03"})
+includes.append({"dir": "2022", "target": "day19"})
+
+matrix = {
+    "dir": [],
+    "target": [],
+    "compiler": ["clang++", "g++"],
+}
+print(
+    "::set-output name=matrix-combinations::"
+    + json.dumps({**matrix, "include": includes})
+)

.github/workflows/test-build.yml

@@ -0,0 +1,44 @@
+name: Test builds
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  setup-matrix:
+    runs-on: ubuntu-latest
+    name: Test changed files
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: Get changed files
+        id: changed-files
+        uses: tj-actions/changed-files@v40
+        with:
+          json: true
+          files: |
+            */src/day*.cpp
+            */src/lib.h*
+            */Makefile
+      # reference: https://stackoverflow.com/a/65094398
+      - name: Setup matrix combinations
+        id: setup-matrix-combinations
+        run: python ${GITHUB_WORKSPACE}/.github/workflows/gen_matrix.py "${{ steps.changed-files.outputs.all_changed_files }}"
+    outputs:
+      matrix-combinations: ${{ steps.setup-matrix-combinations.outputs.matrix-combinations }}
+
+  matrix-job:
+    runs-on: ubuntu-latest
+    needs: setup-matrix
+    strategy:
+      matrix:
+        ${{ fromJson(needs.setup-matrix.outputs.matrix-combinations) }}
+    steps:
+      - name: Build targets
+        run: |
+        cd ${{ matrix.dir }}
+        make -j2 CXX=${{ matrix.compiler }} DISABLE_BEAR=TRUE build/release/${{ matrix.target }} build/debug/${{ matrix.target }}