Enable generation of ROS2 nodes directly from C++ code

.github/workflows/ci.yml

@@ -62,6 +62,10 @@ jobs:
   cpp-tests:
     uses: lf-lang/lingua-franca/.github/workflows/cpp-tests.yml@master
 
+  # Run the C++ integration tests on ROS2.
+  cpp-ros2-tests:
+    uses: lf-lang/lingua-franca/.github/workflows/cpp-ros2-tests.yml@cpp-ros2-platform
+
   # Run the Python integration tests.
   py-tests:
     uses: lf-lang/lingua-franca/.github/workflows/py-tests.yml@master

.github/workflows/cpp-ros2-tests.yml

@@ -0,0 +1,47 @@
+name: C++ tests
+
+on:
+  workflow_call:
+    inputs:
+      compiler-ref:
+        required: false
+        type: string
+      runtime-ref:
+        required: false
+        type: string
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Java JDK
+        uses: actions/setup-java@v1.4.3
+        with:
+          java-version: 11
+      - name: Check out lingual-franca repository
+        uses: actions/checkout@v2
+        with:
+          repository: lf-lang/lingua-franca
+          submodules: true
+          ref: ${{ inputs.compiler-ref }}
+      - name: Check out specific ref of reactor-CPO
+        uses: actions/checkout@v2
+        with:
+          repository: lf-lang/reactor-cpp
+          path: org.lflang/src/lib/cpp/reactor-cpp
+          ref: ${{ inputs.runtime-ref }}
+        if: ${{ inputs.runtime-ref }}
+      - name: Setup ROS2
+        uses: ros-tooling/setup-ros@0.2.2
+        with:
+          required-ros-distributions: galactic
+      - name: Run C++ tests;
+        run: |
+          source /opt/ros/galactic/setup.bash
+          ./gradlew test --tests org.lflang.tests.runtime.CppRos2Test.*
+      - name: Report to CodeCov
+        uses: codecov/codecov-action@v2.1.0
+        with:
+          file: org.lflang.tests/build/reports/xml/jacoco
+          fail_ci_if_error: false
+          verbose: true
+        if: ${{ !inputs.runtime-ref }}  # i.e., if this is part of the main repo's CI

example/Cpp/src/ROS/MinimalPublisher.lf

@@ -0,0 +1,31 @@
+target Cpp {
+    ros2: true
+}
+
+public preamble {=
+    #include "rclcpp/rclcpp.hpp"
+    #include "std_msgs/msg/string.hpp"
+=}
+
+main reactor {
+    private preamble {=
+        // FIXME: forward declaration to make the node visible
+        extern rclcpp::Node* lf_node;
+    =}
+
+    state publisher: {= rclcpp::Publisher<std_msgs::msg::String>::SharedPtr =}
+    state count: unsigned(0)
+
+    timer t(0, 500 ms)
+
+    reaction(startup) {=
+        publisher = lf_node->create_publisher<std_msgs::msg::String>("topic", 10);
+    =}
+
+    reaction(t) {=
+        auto message = std_msgs::msg::String();
+        message.data = "Hello, world! " + std::to_string(count++);
+        reactor::log::Info() << "Publishing: " << message.data;
+        publisher->publish(message);
+    =}
+}

example/Cpp/src/ROS/MinimalSubscriber.lf

@@ -0,0 +1,32 @@
+target Cpp {
+    ros2: true,
+    keepalive: true,
+}
+
+public preamble {=
+    #include "rclcpp/rclcpp.hpp"
+    #include "std_msgs/msg/string.hpp"
+=}
+
+main reactor {
+    private preamble {=
+        // FIXME: forward declaration to make the node visible
+        extern rclcpp::Node* lf_node;
+    =}
+
+    state subscription: {= rclcpp::Subscription<std_msgs::msg::String>::SharedPtr =}
+    state count: unsigned(0)
+
+    physical action message: std::string;
+
+    reaction(startup) -> message {=
+        subscription = lf_node->create_subscription<std_msgs::msg::String>(
+            "topic", 10, [&message](const std_msgs::msg::String::SharedPtr msg) { message.schedule(msg->data); } );
+        // FIXME: Why can't we use a reference type in the lambda argument?
+        // const std_msgs::msg::String::SharedPtr& msg
+    =}
+
+    reaction(message) {=
+        reactor::log::Info() << "I heard: " << *message.get();
+    =}
+}

example/Cpp/src/ROS/README.md

@@ -0,0 +1,5 @@
+This is an LF reimplementation of the ROS 2 minimal publisher and sunscriber
+[example](https://docs.ros.org/en/galactic/Tutorials/Writing-A-Simple-Cpp-Publisher-And-Subscriber.html).
+
+It consists of two LF files, MinimalPublisher and MinimalSubscriber, each
+implementing the corresponding nodes from the original example.

org.lflang.tests/src/org/lflang/tests/TestBase.java

@@ -139,6 +139,7 @@ public static class Message {
         public static final String DESC_AS_CCPP = "Running C tests as CCpp.";
         public static final String DESC_FOUR_THREADS = "Run non-concurrent and non-federated tests (threads = 4).";
         public static final String DESC_SCHED_SWAPPING = "Running with non-default runtime scheduler ";
+        public static final String DESC_ROS2 = "Running tests using ROS2.";
 
         /* Missing dependency messages */
         public static final String MISSING_DOCKER = "Executable 'docker' not found or 'docker' daemon thread not running";