add return type for DBG

jyf111 · Nov 11, 2023 · e52ce5b · e52ce5b
1 parent dbb6d66
commit e52ce5b
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Showing 2 changed files with 57 additions and 14 deletions.
diff --git a/examples/demo.cpp b/examples/demo.cpp
@@ -11,18 +11,42 @@ struct data {
   };
   dir dr;
 };
+struct Bad {
+  int x, y;
+};
+DBG_REGISTER(Bad, x, y)
+struct MyStruct {
+  struct gps {
+    double latitude;
+    double longitude;
+  };
+  gps location;
+
+  struct image {
+    uint16_t width;
+    uint16_t height;
+    std::string url;
+
+    struct format {
+      enum class type { bayer_10bit, yuyv_422 };
+      type type;
+    };
+    format format;
+  };
+  image thumbnail;
+};
+
+MyStruct s{ { 41.13, -73.70 }, { 480, 340, "https://foo/bar/baz.jpg", { MyStruct::image::format::type::yuyv_422 } } };
 int main() {
   int a = 2;
   short b = 3;
   long long x = 7;
   int &ref = a;
   long &&rref = 4l;
   data d{ 1, 2, 3, "hello", { 6, 0, 8 } };
-  DBG(a);
-  DBG(b);
-  DBG(x);
-  DBG(ref);
-  DBG(rref);
+  DBG(a, b, x);
+  DBG(ref, rref);
+  DBG(d);
   std::deque<int> dq{ 1, 2 };
   DBG(dq);
   DBG((std::vector<int>{ 1, 2 }));
@@ -48,7 +72,6 @@ int main() {
   DBG(ttt);
   DBG(true);
   DBG(dbg::type<char[2][3][4]>());
-  // DBG();
   DBG("This is a message");
   DBG(std::string("This is a string"));
   const char *msg = "MMMM";
@@ -58,5 +81,10 @@ int main() {
   int y = DBG(x) + 2;
   const int32_t A = 2;
   const int32_t B = DBG(3 * A) + 1;
+  DBG(B);
+  DBG(s);
+  Bad bad = { 2, 5 };
+  DBG(bad);
+  DBG();
   return 0;
 }
diff --git a/include/dbg.h b/include/dbg.h
@@ -801,6 +801,17 @@ void print(std::ostream &os, const base<T, N> &value) {
 }
 }  // namespace printer
 
+template <typename T, typename... U>
+struct last {
+  using type = typename last<U...>::type;
+};
+template <typename T>
+struct last<T> {
+  using type = T;
+};
+template <typename... T>
+using last_t = typename last<T...>::type;
+
 class Debugger {
  public:
   Debugger(const char *file, int line, const char *func) : os_(config::get_stream()) {
@@ -816,14 +827,14 @@ class Debugger {
 
   void print() { os_ << (printer::location_print(location_) + '\n'); }
   template <typename... T>
-  void print(const std::initializer_list<std::string> &exprs, const std::initializer_list<std::string> &type_names,
-             T &&...values) {
-    print_impl(exprs.begin(), type_names.begin(), std::forward<T>(values)...);
+  auto print(const std::initializer_list<std::string> &exprs, const std::initializer_list<std::string> &type_names,
+             T &&...values) -> last_t<T...> {
+    return print_impl(exprs.begin(), type_names.begin(), std::forward<T>(values)...);
   }
 
  private:
   template <typename T>
-  void print_impl(const std::string *expr_iter, const std::string *type_name_iter, T &&value) {
+  T &&print_impl(const std::string *expr_iter, const std::string *type_name_iter, T &&value) {
     std::stringstream ss;
     ss << printer::location_print(location_) << ' ';
     ss << printer::expression_print(*expr_iter) << " = ";
@@ -832,20 +843,24 @@ class Debugger {
     ss << printer::value_print(ss2.str());
     ss << " (" << printer::type_print(*type_name_iter) << ")\n";
     os_ << ss.str();
+    return std::forward<T>(value);
   }
   template <size_t N>
-  void print_impl(const std::string *, const std::string *, const char (&value)[N]) {
+  auto print_impl(const std::string *, const std::string *, const char (&value)[N]) -> decltype(value) {
     os_ << (printer::location_print(location_) + ' ' + printer::message_print(value) + '\n');
+    return value;
   }
   template <typename T>
-  void print_impl(const std::string *, const std::string *type_name_iter, type<T> &&value) {
+  type<T> &&print_impl(const std::string *, const std::string *type_name_iter, type<T> &&value) {
     os_ << (printer::location_print(location_) + ' ' +
             printer::type_print(*type_name_iter + " [sizeof " + std::to_string(sizeof(T)) + "]") + '\n');
+    return std::forward<type<T>>(value);
   }
   template <typename T, typename... U>
-  void print_impl(const std::string *expr_iter, const std::string *type_name_iter, T &&value, U &&...rest) {
+  auto print_impl(const std::string *expr_iter, const std::string *type_name_iter, T &&value, U &&...rest)
+      -> last_t<U...> {
     print_impl(expr_iter, type_name_iter, std::forward<T>(value));
-    print_impl(expr_iter + 1, type_name_iter + 1, std::forward<U>(rest)...);
+    return print_impl(expr_iter + 1, type_name_iter + 1, std::forward<U>(rest)...);
   }
 
   std::ostream &os_;