From a5a756a20e37debd4e559b5fa0571004e07a58d1 Mon Sep 17 00:00:00 2001
From: Glen Fraser <holaglen@gmail.com>
Date: Sun, 21 Apr 2019 20:07:19 +0200
Subject: [PATCH] Add pair_conversion registration helper with unit test

---
 .../dispatchkit/type_conversions.hpp          | 17 ++++++++++++++
 unittests/compiled_tests.cpp                  | 23 +++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/chaiscript/dispatchkit/type_conversions.hpp b/include/chaiscript/dispatchkit/type_conversions.hpp
index 9d07ddaa..91ee1336 100644
--- a/include/chaiscript/dispatchkit/type_conversions.hpp
+++ b/include/chaiscript/dispatchkit/type_conversions.hpp
@@ -654,6 +654,23 @@ namespace chaiscript
 
       return chaiscript::make_shared<detail::Type_Conversion_Base, detail::Type_Conversion_Impl<decltype(func)>>(user_type<std::map<std::string, Boxed_Value>>(), user_type<To>(), func);
     }
+
+  template<typename Left, typename Right>
+    Type_Conversion pair_conversion()
+    {
+      auto func = [](const Boxed_Value &t_bv) -> Boxed_Value {
+        const std::pair<Boxed_Value, Boxed_Value> &from_pair = detail::Cast_Helper<const std::pair<Boxed_Value, Boxed_Value> &>::cast(t_bv, nullptr);
+
+        auto pair = std::make_pair(
+          detail::Cast_Helper<Left>::cast(from_pair.first, nullptr),
+          detail::Cast_Helper<Right>::cast(from_pair.second, nullptr)
+        );
+
+        return Boxed_Value(std::move(pair));
+      };
+
+      return chaiscript::make_shared<detail::Type_Conversion_Base, detail::Type_Conversion_Impl<decltype(func)>>(user_type<std::pair<Boxed_Value, Boxed_Value>>(), user_type<std::pair<Left, Right>>(), func);
+    }
 }
 
 
diff --git a/unittests/compiled_tests.cpp b/unittests/compiled_tests.cpp
index 76c31bc8..a5261655 100644
--- a/unittests/compiled_tests.cpp
+++ b/unittests/compiled_tests.cpp
@@ -996,6 +996,29 @@ TEST_CASE("Map conversions")
 }
 
 
+TEST_CASE("Pair conversions")
+{
+  chaiscript::ChaiScript_Basic chai(create_chaiscript_stdlib(),create_chaiscript_parser());
+  chai.add(chaiscript::pair_conversion<std::string, std::string>());
+  chai.add(chaiscript::pair_conversion<int, double>());
+
+  {
+    const auto p = chai.eval<std::pair<std::string, std::string>>(R"cs(
+      Pair("chai", "script");
+    )cs");
+    CHECK(p.first == std::string{"chai"});
+    CHECK(p.second == "script");
+  }
+  {
+    const auto p = chai.eval<std::pair<int, double>>(R"cs(
+      Pair(5, 3.14);
+    )cs");
+    CHECK(p.first == 5);
+    CHECK(p.second == Approx(3.14));
+  }
+}
+
+
 TEST_CASE("Parse floats with non-posix locale")
 {
 #ifdef CHAISCRIPT_MSVC