From e33cfdd668366006646259e91ef7c6e9a8ae7cd7 Mon Sep 17 00:00:00 2001
From: Bowen Fu <BowenFu@users.noreply.github.com>
Date: Fri, 24 Jun 2022 08:19:57 +0800
Subject: [PATCH] Fix Id. (#12)

Fix id

Co-authored-by: Bowen Fu <missing>
---
 .github/workflows/cmake.yml |  2 +-
 CMakeLists.txt              |  2 +-
 include/hspp.h              | 37 ++++++++++++++++++++++++++-----------
 test/hspp/test.cpp          | 24 ++++++++----------------
 4 files changed, 36 insertions(+), 29 deletions(-)

diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index be7a3a0..390ef14 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -39,5 +39,5 @@ jobs:
       working-directory: ${{github.workspace}}/build
       # Execute tests defined by the CMake configuration.  
       # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
-      run: ctest --output-on-failure --parallel 4 -C ${{env.BUILD_TYPE}}
+      run: ctest --output-on-failure --parallel -C ${{env.BUILD_TYPE}}
       
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ac1b764..f1fd581 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -18,7 +18,7 @@ message(STATUS "CXX_STANDARD: ${CMAKE_CXX_STANDARD}")
 list(APPEND
     BASE_COMPILE_FLAGS
     "$<$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>,$<CXX_COMPILER_ID:GNU>>:-Wall;-Wextra;-pedantic;-Werror;-Wno-parentheses;-Wno-shadow;-Wconversion;-Wsign-conversion>"
-        "$<$<CXX_COMPILER_ID:MSVC>:/W4>") # /WX for -Werror
+        "$<$<CXX_COMPILER_ID:MSVC>:/W4;/Zm20>") # /WX for -Werror
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
diff --git a/include/hspp.h b/include/hspp.h
index ee7894a..b000575 100644
--- a/include/hspp.h
+++ b/include/hspp.h
@@ -44,24 +44,37 @@ auto overload(Ts&&... ts)
 
 namespace doN
 {
+// make sure Id is not a const obj.
 template <typename T>
 class Id
 {
-    // should be std::shared_ptr<std::optional<T>>
-    std::shared_ptr<T> mT = std::make_shared<T>();
+    using OptT = std::optional<T>;
+    std::shared_ptr<OptT> mT = std::make_shared<OptT>();
 public:
     constexpr Id() = default;
     constexpr auto const& value() const
     {
         if (!mT)
+        {
+            throw std::runtime_error{"Invalid id!"};
+        }
+        if (!mT->has_value())
         {
             throw std::runtime_error{"Id has no binding!"};
         }
-        return *mT;
+        return mT->value();
     }
-    constexpr void bind(T v)
+    constexpr void bind(T v) const
     {
-        *mT = std::move(v);
+        // if (mT->has_value())
+        // {
+        //     throw std::runtime_error{"Id already has a binding!"};
+        // }
+        const_cast<OptT&>(*mT) = std::move(v);
+    }
+    constexpr void reset() const
+    {
+        const_cast<OptT&>(*mT) = OptT{};
     }
 };
 
@@ -3251,7 +3264,7 @@ class Traversable<std::tuple, Args...> : public TraversableBase<std::tuple, Args
     {
         constexpr auto sizeMinusOne = std::tuple_size_v<std::decay_t<decltype(in)>> - 1;
         auto last = std::get<sizeMinusOne>(in);
-        auto const func = toGFunc<1>([in=std::move(in)](auto&& lastElem)
+        auto const func = toGFunc<1>([in=std::forward<decltype(in)>(in)](auto&& lastElem)
         {
             constexpr auto sizeMinusOne = std::tuple_size_v<std::decay_t<decltype(in)>> - 1;
             return std::tuple_cat(subtuple<0, sizeMinusOne>(std::move(in)), std::make_tuple(lastElem));
@@ -3417,14 +3430,14 @@ class DeMonad
     {
         return mM;
     }
-    constexpr auto id() const -> std::reference_wrapper<Id<T>>
+    constexpr auto id() const -> Id<T>
     {
         return mId;
     }
 
 private:
     std::reference_wrapper<M const> mM;
-    std::reference_wrapper<Id<T>> mId;
+    Id<T> mId;
 };
 
 template <typename... Ts>
@@ -3508,13 +3521,15 @@ BIN_OP_FOR_NULLARY(<)
 BIN_OP_FOR_NULLARY(&&)
 
 template <typename T, typename BodyBaker>
-constexpr auto funcWithParams(std::reference_wrapper<Id<T>> const& param, BodyBaker const& bodyBaker)
+constexpr auto funcWithParams(Id<T> const& param, BodyBaker const& bodyBaker)
 {
     return [=](T const& t)
     {
         // bind before baking body.
-        param.get().bind(t);
-        return evaluate_(bodyBaker());
+        const_cast<Id<T>&>(param).bind(t);
+        auto result = evaluate_(bodyBaker());
+        // const_cast<Id<T>&>(param).reset();
+        return result;
     };
 }
 
diff --git a/test/hspp/test.cpp b/test/hspp/test.cpp
index 4863006..48b9fa1 100644
--- a/test/hspp/test.cpp
+++ b/test/hspp/test.cpp
@@ -1421,24 +1421,16 @@ constexpr auto isSpace = toFunc<> | [](char c)
 
 const auto space = many || sat | isSpace;
 
-// // This will fail some tests.
-// constexpr auto token = toGFunc<1> | [](auto p)
-// {
-//     using A = DataType<decltype(p)>;
-//     doN::Id<A> a;
-//     return doN::do_(
-//         a <= p,
-//         space,
-//         return_ | a
-//     );
-// };
-
+// This will fail some tests.
 constexpr auto token = toGFunc<1> | [](auto p)
 {
-    return p >>= [](auto a) { return
-        space >>
-        (return_ | a);
-    };
+    using A = DataType<std::decay_t<decltype(p)>>;
+    doN::Id<A> a;
+    return doN::do_(
+        a <= p,
+        space,
+        return_ | a
+    );
 };
 
 constexpr auto symb = token <o> string;