From 70a2b88898c3fd452f9e16a6c706d17a4f4b1460 Mon Sep 17 00:00:00 2001
From: q66 <daniel@octaforge.org>
Date: Sun, 11 Sep 2016 19:57:42 +0200
Subject: [PATCH] allow non-static methods to be bound to Function

---
 ostd/functional.hh  |  9 ++------
 ostd/type_traits.hh | 54 ++++++++++++++++++++++++++++-----------------
 2 files changed, 36 insertions(+), 27 deletions(-)

diff --git a/ostd/functional.hh b/ostd/functional.hh
index aa731e2..2f58dad 100644
--- a/ostd/functional.hh
+++ b/ostd/functional.hh
@@ -571,16 +571,11 @@ namespace detail {
         return !!f;
     }
 
-    template<typename F, typename ...A>
-    inline auto func_invoke_helper(F &&f, A &&...args) {
-        return forward<F>(f)(forward<A>(args)...);
-    }
-
     template<typename R>
     struct FuncInvokeVoidReturnWrapper {
         template<typename ...A>
         static R call(A &&...args) {
-            return func_invoke_helper(forward<A>(args)...);
+            return func_invoke(forward<A>(args)...);
         }
     };
 
@@ -588,7 +583,7 @@ namespace detail {
     struct FuncInvokeVoidReturnWrapper<void> {
         template<typename ...A>
         static void call(A &&...args) {
-            func_invoke_helper(forward<A>(args)...);
+            func_invoke(forward<A>(args)...);
         }
     };
 
diff --git a/ostd/type_traits.hh b/ostd/type_traits.hh
index 3bfb90e..d39c444 100644
--- a/ostd/type_traits.hh
+++ b/ostd/type_traits.hh
@@ -1452,7 +1452,24 @@ namespace detail {
 
 #define OSTD_FWD(T, _v) static_cast<T &&>(_v)
     template<typename ...A>
-    auto func_invoke(InvokeAny, A &&...) -> InvokeNat;
+    inline auto func_invoke(InvokeAny, A &&...) -> InvokeNat;
+
+    /* forward declarations, later defined in functional */
+    template<
+        typename F, typename T, typename ...A,
+        typename = EnableIf<
+            IsMemberFunctionPointer<RemoveReference<F>> &&
+            IsBaseOf<
+                RemoveReference<MemberPointerClass<RemoveReference<F>>>,
+                RemoveReference<T>
+            >
+        >
+    >
+    inline auto func_invoke(F &&f, T &&v, A &&...args) ->
+        decltype((OSTD_FWD(T, v).*f)(OSTD_FWD(A, args)...))
+    {
+        return (OSTD_FWD(T, v).*f)(OSTD_FWD(A, args)...);
+    }
 
     template<
         typename F, typename T, typename ...A,
@@ -1464,21 +1481,11 @@ namespace detail {
             >
         >
     >
-    auto func_invoke(F &&f, T &&v, A &&...args) ->
-        decltype((OSTD_FWD(T, v).*f)(OSTD_FWD(A, args)...));
-
-    template<
-        typename F, typename T, typename ...A,
-        typename = EnableIf<
-            IsMemberFunctionPointer<RemoveReference<F>> &&
-            IsBaseOf<
-                RemoveReference<MemberPointerClass<RemoveReference<F>>>,
-                RemoveReference<T>
-            >
-        >
-    >
-    auto func_invoke(F &&f, T &&v, A &&...args) ->
-        decltype(((*OSTD_FWD(T, v)).*f)(OSTD_FWD(A, args)...));
+    inline auto func_invoke(F &&f, T &&v, A &&...args) ->
+        decltype(((*OSTD_FWD(T, v)).*f)(OSTD_FWD(A, args)...))
+    {
+        return ((*OSTD_FWD(T, v)).*f)(OSTD_FWD(A, args)...);
+    }
 
     template<
         typename F, typename T,
@@ -1490,7 +1497,9 @@ namespace detail {
             >
         >
     >
-    auto func_invoke(F &&f, T &&v) -> decltype(OSTD_FWD(T, v).*f);
+    inline auto func_invoke(F &&f, T &&v) -> decltype(OSTD_FWD(T, v).*f) {
+        return OSTD_FWD(T, v).*f;
+    }
 
     template<
         typename F, typename T,
@@ -1502,11 +1511,16 @@ namespace detail {
             >
         >
     >
-    auto func_invoke(F &&f, T &&v) -> decltype((*OSTD_FWD(T, v)).*f);
+    inline auto func_invoke(F &&f, T &&v) -> decltype((*OSTD_FWD(T, v)).*f) {
+        return (*OSTD_FWD(T, v)).*f;
+    }
 
     template<typename F, typename ...A>
-    auto func_invoke(F &&f, A &&...args) ->
-        decltype(OSTD_FWD(F, f)(OSTD_FWD(A, args)...));
+    inline auto func_invoke(F &&f, A &&...args) ->
+        decltype(OSTD_FWD(F, f)(OSTD_FWD(A, args)...))
+    {
+        return OSTD_FWD(F, f)(OSTD_FWD(A, args)...);
+    }
 #undef OSTD_FWD
 
     template<typename F, typename ...A>