add example

src/struct_pb/examples/CMakeLists.txt

@@ -0,0 +1,24 @@
+if("${yaLanTingLibs_SOURCE_DIR}" STREQUAL "${CMAKE_SOURCE_DIR}")
+  # If this is a subproject in ylt
+    set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/output/examples)
+else()
+  # else find installed yalantinglibs
+    cmake_minimum_required(VERSION 3.15)
+    project(struct_pb_examples)
+    if(NOT CMAKE_BUILD_TYPE)
+        set(CMAKE_BUILD_TYPE "Release")
+    endif()
+    set(CMAKE_CXX_STANDARD 17)
+    set(CMAKE_CXX_STANDARD_REQUIRED ON)
+    set(CMAKE_INCLUDE_CURRENT_DIR ON)
+  # if you have install ylt  
+    find_package(yalantinglibs REQUIRED)
+    link_libraries(yalantinglibs::yalantinglibs)
+  # else 
+  # include_directories(include)
+  # include_directories(include/ylt/thirdparty)
+endif()
+
+add_executable(struct_pb_examples
+        main.cpp
+        )

src/struct_pb/examples/main.cpp

@@ -0,0 +1,27 @@
+#include <cassert>
+#include <iostream>
+#include <ylt/struct_pb.hpp>
+
+struct my_struct : struct_pb::pb_base {
+  int x;
+  bool y;
+  iguana::fixed64_t z;
+};
+REFLECTION(my_struct, x, y, z);
+
+struct nest : struct_pb::pb_base {
+  std::string name;
+  my_struct value;
+  int var;
+};
+REFLECTION(nest, name, value, var);
+
+int main() {
+  nest v{0, "Hi", {0, 1, false, 3}, 5}, v2{};
+  std::string s;
+  struct_pb::to_pb(v, s);
+  struct_pb::from_pb(v2, s);
+  assert(v.var == v2.var);
+  assert(v.value.y == v2.value.y);
+  assert(v.value.z == v2.value.z);
+}