Add github CI

Author: rdevshp

.github/workflows/ci.yml

@@ -0,0 +1,74 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lean:
+    name: Lean build and tests
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Install elan
+        shell: bash
+        run: |
+          set -euo pipefail
+          curl --proto '=https' --tlsv1.2 -sSf \
+            https://raw.githubusercontent.com/leanprover/elan/master/elan-init.sh \
+            -o /tmp/elan-init.sh
+          sh /tmp/elan-init.sh -y --default-toolchain none
+          echo "$HOME/.elan/bin" >> "$GITHUB_PATH"
+
+      - name: Install pinned Lean toolchain
+        shell: bash
+        run: |
+          set -euo pipefail
+          export PATH="$HOME/.elan/bin:$PATH"
+          toolchain="$(tr -d '[:space:]' < lean-toolchain)"
+          elan toolchain install "$toolchain"
+          lean --version
+          lake --version
+
+      - name: Build Lean library
+        run: lake build CSem
+
+      - name: Run Lean test executables
+        run: |
+          lake exe parser_generator_tests
+          lake exe parser_tests
+          lake exe parser_vy_importer_tests
+          lake exe parser_vy_full_grammar_tests
+          lake exe parser_vy_lr_validation
+          lake exe semantics_tests
+
+      - name: Build export tools
+        run: lake build c_parse_export c_elab_export
+
+  rust:
+    name: Rust parser importer
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Select stable Rust
+        run: rustup default stable
+
+      - name: Check parser importer
+        run: cargo check --manifest-path tools/rust/Cargo.toml --locked