Adding simple module example.

CMakeLists.txt

@@ -196,3 +196,12 @@ if(flow-ui_INSTALL)
 
   write_basic_package_version_file(${PROJECT_NAME}ConfigVersion.cmake COMPATIBILITY SameMajorVersion)
 endif()
+
+# -----------------------------------------------------------------------------
+# Examples
+# -----------------------------------------------------------------------------
+
+option(BUILD_EXAMPLES OFF)
+if (BUILD_EXAMPLES)
+  add_subdirectory(examples)
+endif()

examples/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(simple_module)

examples/simple_module/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.10)
+
+project(simple_module VERSION 1.0.0 LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+if(APPLE)
+    enable_language(OBJC)
+endif()
+
+add_library(${PROJECT_NAME} SHARED src/register.cpp)
+target_compile_definitions(${PROJECT_NAME} PRIVATE FLOW_SIMPLE_EXPORT)
+
+if(MSVC)
+  set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
+  target_compile_options(${PROJECT_NAME} PRIVATE /W4)
+endif()
+
+add_dependencies(${PROJECT_NAME} flow-core)
+target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
+target_link_libraries(${PROJECT_NAME} PUBLIC flow-core)

examples/simple_module/include/Example.hpp

@@ -0,0 +1,54 @@
+// Copyright (c) 2024,Cisco Systems, Inc.
+// All rights reserved.
+
+#pragma once
+
+#include <flow/core/Node.hpp>
+#include <flow/core/NodeData.hpp>
+
+#include <string>
+
+namespace flow::simple
+{
+class ExampleNode : public Node
+{
+  public:
+    explicit ExampleNode(const std::string& uuid_str, const std::string& name, std::shared_ptr<Env> env)
+        : Node(uuid_str, flow::TypeName_v<ExampleNode>, name, std::move(env))
+    {
+        AddInput<std::string>("name", "Input name");
+        AddOutput<std::string>("greeting", "A greeting to the specified user");
+    }
+
+    virtual ~ExampleNode() = default;
+
+  protected:
+    void Compute() override
+    {
+        if (auto name_data = GetInputData<std::string>("name"))
+        {
+            const std::string& name = name_data->Get();
+            SetOutputData("greeting", flow::MakeNodeData("Hello " + name + "!"));
+        }
+    }
+
+    json SaveInputs() const override
+    {
+        if (auto name_data = GetInputData<std::string>("name"))
+        {
+            const std::string& name = name_data->Get();
+            return {{"name", name}};
+        }
+
+        return {};
+    }
+
+    void RestoreInputs(const json& j) override
+    {
+        if (j.contains("name"))
+        {
+            SetInputData("name", flow::MakeNodeData(j["name"].get_ref<const std::string&>()));
+        }
+    }
+};
+} // namespace flow::simple

examples/simple_module/src/register.cpp

@@ -0,0 +1,29 @@
+#include "Example.hpp"
+
+#include <flow/core/NodeFactory.hpp>
+
+#ifdef FLOW_WINDOWS
+#ifdef FLOW_SIMPLE_EXPORT
+#define FLOW_SIMPLE_API __declspec(dllexport) FLOW_CORE_CALL
+#else
+#define FLOW_SIMPLE_API __declspec(dllimport) FLOW_CORE_CALL
+#endif
+#else
+#define FLOW_SIMPLE_API
+#endif
+
+extern "C"
+{
+    namespace flow::simple
+    {
+    void FLOW_SIMPLE_API RegisterModule(std::shared_ptr<flow::NodeFactory> factory)
+    {
+        factory->RegisterNodeClass<ExampleNode>("example", "Example");
+    }
+
+    void FLOW_SIMPLE_API UnregisterModule(std::shared_ptr<flow::NodeFactory> factory)
+    {
+        factory->UnregisterNodeClass<ExampleNode>("example");
+    }
+    } // namespace flow::simple
+}