From 9c812552a97a3fb934eb9bef54eb2f5e4a708deb Mon Sep 17 00:00:00 2001
From: Chanwoo Ahn <cwahn@arsvivendi.io>
Date: Wed, 10 Apr 2024 12:23:24 +0900
Subject: [PATCH] feat: Implement pattern check with test

---
 include/efp/enum.hpp   |  4 +--
 include/efp/maybe.hpp  | 57 +++++++++++++++++++++++++++++-------------
 include/efp/meta.hpp   | 16 ++++++------
 test/efp/enum_test.hpp |  1 +
 4 files changed, 50 insertions(+), 28 deletions(-)

diff --git a/include/efp/enum.hpp b/include/efp/enum.hpp
index db7893a..e81e4f3 100644
--- a/include/efp/enum.hpp
+++ b/include/efp/enum.hpp
@@ -239,8 +239,6 @@ namespace detail {
     public:
         constexpr static uint8_t alt_num = sizeof...(As) + 1;
 
-        // constexpr static uint8_t switch_size = power_2_ceiling(alt_num);
-
         // Default constructor initializes the first alternative with default constructor
         EnumBase() : _index {0} {
             new (reinterpret_cast<A*>(&_storage)) A {};
@@ -410,7 +408,7 @@ namespace detail {
 
     private:
         template<typename Alt>
-        struct AltIndex: Find<IsSameUnary<ReferenceRemoved<Alt>>::template Binded, A, As...> {};
+        using AltIndex = Find<IsSameUnary<ReferenceRemoved<Alt>>::template Binded, A, As...>;
 
         // Assume that the index is altready bounded
         template<uint8_t i>
diff --git a/include/efp/maybe.hpp b/include/efp/maybe.hpp
index 7c8e9e4..d6d04a5 100644
--- a/include/efp/maybe.hpp
+++ b/include/efp/maybe.hpp
@@ -6,12 +6,22 @@
 #include "efp/trait.hpp"
 
 namespace efp {
+
 struct Nothing {};
 
 constexpr Nothing nothing;
 
 // Specialization of Enum for Maybe
 
+template<typename A>
+using Maybe = Enum<Nothing, A>;
+
+template<typename A>
+struct IsMaybe: False {};
+
+template<typename A>
+struct IsMaybe<Maybe<A>>: True {};
+
 template<typename A>
 class Enum<Nothing, A>: public detail::EnumBase<Nothing, A> {
 public:
@@ -44,22 +54,44 @@ class Enum<Nothing, A>: public detail::EnumBase<Nothing, A> {
     }
 
     template<typename F>
-    auto fmap(const F& f) -> Enum<Nothing, InvokeResult<F, A>> {
+    static Enum<Nothing, A> pure(const A& a) {
+        return a;
+    }
+
+    template<typename F>
+    auto fmap(const F& f) -> Enum<Nothing, InvokeResult<F, A>> const {
         if (has_value())
             return f(value());
         else
             return nothing;
     }
-};
 
-template<typename A>
-using Maybe = Enum<Nothing, A>;
+    template<typename F>
+    auto ap(const Enum<Nothing, F>& mf) -> Enum<Nothing, InvokeResult<F, A>> const {
+        if (has_value() && mf.has_value())
+            return mf.value()(value());
+        else
+            return nothing;
+    }
 
-template<typename A>
-struct IsMaybe: False {};
+    template<typename F>
+    auto bind(const F& f)
+        -> EnableIf<IsMaybe<InvokeResult<F, A>>::value, InvokeResult<F, A>> const {
+        if (has_value())
+            return f(value());
+        else
+            return nothing;
+    }
 
-template<typename A>
-struct IsMaybe<Maybe<A>>: True {};
+    template<typename F>
+    auto operator>>=(const F& f)
+        -> EnableIf<IsMaybe<InvokeResult<F, A>>::value, InvokeResult<F, A>> const {
+        if (has_value())
+            return f(value());
+        else
+            return nothing;
+    }
+};
 
 // Element specializetion for Maybe
 template<typename A>
@@ -102,15 +134,6 @@ auto bind(const Maybe<A>& ma, const F& f)
         return nothing;
 }
 
-template<typename A, typename F>
-auto operator>>=(const Maybe<A>& ma, const F& f)
-    -> EnableIf<IsMaybe<InvokeResult<F, A>>::value, InvokeResult<F, A>> {
-    if (ma)
-        return f(ma.value());
-    else
-        return nothing;
-}
-
 }  // namespace efp
 
 #endif
\ No newline at end of file
diff --git a/include/efp/meta.hpp b/include/efp/meta.hpp
index e2f7f4f..6e531f7 100644
--- a/include/efp/meta.hpp
+++ b/include/efp/meta.hpp
@@ -820,24 +820,24 @@ constexpr A _product(const A (&as)[n]) {
 }
 
 // All
-// ! Deprecated because of performance issue. Use foldl instead
+// ! Not suitable for library implementation because of compile-time performance issue
 template<typename A, typename... As>
-struct All: Bool<_all({A::value, As::value...})> {};
+using All = Bool<_all({A::value, As::value...})>;
 
 // Any
-// ! Deprecated because of performance issue. Use foldl instead
+// ! Not suitable for library implementation because of compile-time performance issue
 template<typename A, typename... As>
-struct Any: Bool<_any({A::value, As::value...})> {};
+using Any = Bool<_any({A::value, As::value...})>;
 
 // Minimum
-// ! Deprecated because of performance issue. Use foldl instead
+// ! Not suitable for library implementation because of compile-time performance issue
 template<typename A, typename... As>
-struct Minimum: CtConst<typename A::value_type, _minimum({A::value, As::value...})> {};
+using Mininum = CtConst<typename A::value_type, _minimum({A::value, As::value...})>;
 
 // Maximum
-// ! Deprecated because of performance issue. Use foldl instead
+// ! Not suitable for library implementation because of compile-time performance issue
 template<typename A, typename... As>
-struct Maximum: CtConst<typename A::value_type, _maximum({A::value, As::value...})> {};
+using Maximum = CtConst<typename A::value_type, _maximum({A::value, As::value...})>;
 
 // Common
 template<typename... As>
diff --git a/test/efp/enum_test.hpp b/test/efp/enum_test.hpp
index bf018c3..484e799 100644
--- a/test/efp/enum_test.hpp
+++ b/test/efp/enum_test.hpp
@@ -369,6 +369,7 @@ TEST_CASE("enum_match") {
         // ! Sould be failed to get compiled and show static assert message on top
         // a.match([&](int x) { b += 1; }, [&](double _) { b += 1; });
         // a.match([&](int x) { b += 1; }, [&](False _) {}, [&]() {});
+        // a.match([&]() {}, [&](int x) { b += 1; });
 
         CHECK(b == 0.);
     }