Fix #68 : Store value instead of ref in PatternPair. (#70)

* Fix #68

* Accept function type

Co-authored-by: Bowen Fu <missing>

develop/matchit/patterns.h

@@ -309,8 +309,8 @@ namespace matchit
             constexpr auto execute() const { return mHandler(); }
 
         private:
-            Pattern const &mPattern;
-            Func const &mHandler;
+            Pattern const mPattern;
+            Func const mHandler;
         };
 
         template <typename Pattern, typename Pred>

include/matchit.h

@@ -616,8 +616,8 @@ namespace matchit
             constexpr auto execute() const { return mHandler(); }
 
         private:
-            Pattern const &mPattern;
-            Func const &mHandler;
+            Pattern const mPattern;
+            std::conditional_t<std::is_function_v<Func>, Func const&, Func const> mHandler;
         };
 
         template <typename Pattern, typename Pred>

sample/CMakeLists.txt

@@ -48,6 +48,7 @@ Extractor-Pattern
 Predicate-based-Discriminator
 Closed-Class-Hierarchy
 Matcher-within
+visit
 )
 
 foreach(sample ${MATCHIT_SAMPLES})

sample/visit.cpp

@@ -0,0 +1,52 @@
+#include "matchit.h"
+
+#include <string>
+#include <iostream>
+
+template <typename T>
+auto constexpr visitPat = [](auto func)
+{
+    using namespace matchit;
+
+    return as<T>(meet([func](auto&& param) {
+            func(param);
+            return true;
+        }));
+};
+
+template <typename T>
+auto constexpr visit = [](auto func)
+{
+    using namespace matchit;
+
+    return pattern | visitPat<T>(func) = []{};
+};
+
+template <typename T>
+void print(T&& x)
+{
+    using namespace matchit;
+
+    match(x)(
+        visit<std::string>(
+            [](const std::string& text) {
+                std::cout << "Text message: " << text << std::endl;
+            }),
+        visit<int32_t>(
+            [](const int32_t num) {
+                std::cout << "Number: " << num << std::endl;
+            })
+        );
+}
+
+int main()
+{
+    using namespace matchit;
+
+    std::variant<int32_t, std::string> v1 = "123";
+    std::variant<int32_t, std::string> v2 = 123;
+
+    print(v1);
+    print(v2);
+    return 0; 
+}