From c0d41a880a239b6c4819ab7c43fd78718d1e5d0c Mon Sep 17 00:00:00 2001
From: Glen Fernandes <glen.fernandes@gmail.com>
Date: Sat, 22 Sep 2018 15:11:32 -0400
Subject: [PATCH] Drop dependency on MPL

---
 include/boost/function/function_base.hpp     | 48 ++++++++++----------
 include/boost/function/function_template.hpp | 22 ++++-----
 2 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/include/boost/function/function_base.hpp b/include/boost/function/function_base.hpp
index c1dbabd..b20a523 100644
--- a/include/boost/function/function_base.hpp
+++ b/include/boost/function/function_base.hpp
@@ -26,13 +26,13 @@
 #include <boost/type_traits/is_volatile.hpp>
 #include <boost/type_traits/composite_traits.hpp>
 #include <boost/ref.hpp>
-#include <boost/mpl/if.hpp>
+#include <boost/type_traits/conditional.hpp>
 #include <boost/config/workaround.hpp>
 #include <boost/type_traits/alignment_of.hpp>
 #ifndef BOOST_NO_SFINAE
 #include <boost/type_traits/enable_if.hpp>
 #else
-#  include "boost/mpl/bool.hpp"
+#include <boost/type_traits/integral_constant.hpp>
 #endif
 #include <boost/function_equal.hpp>
 #include <boost/function/function_fwd.hpp>
@@ -152,15 +152,15 @@ namespace boost {
       template<typename F>
       class get_function_tag
       {
-        typedef typename mpl::if_c<(is_pointer<F>::value),
+        typedef typename conditional<(is_pointer<F>::value),
                                    function_ptr_tag,
                                    function_obj_tag>::type ptr_or_obj_tag;
 
-        typedef typename mpl::if_c<(is_member_pointer<F>::value),
+        typedef typename conditional<(is_member_pointer<F>::value),
                                    member_ptr_tag,
                                    ptr_or_obj_tag>::type ptr_or_obj_or_mem_tag;
 
-        typedef typename mpl::if_c<(is_reference_wrapper<F>::value),
+        typedef typename conditional<(is_reference_wrapper<F>::value),
                                    function_obj_ref_tag,
                                    ptr_or_obj_or_mem_tag>::type or_ref_tag;
 
@@ -328,7 +328,7 @@ namespace boost {
         // Function objects that fit in the small-object buffer.
         static inline void
         manager(const function_buffer& in_buffer, function_buffer& out_buffer,
-                functor_manager_operation_type op, mpl::true_)
+                functor_manager_operation_type op, true_type)
         {
           functor_manager_common<Functor>::manage_small(in_buffer,out_buffer,op);
         }
@@ -336,7 +336,7 @@ namespace boost {
         // Function objects that require heap allocation
         static inline void
         manager(const function_buffer& in_buffer, function_buffer& out_buffer,
-                functor_manager_operation_type op, mpl::false_)
+                functor_manager_operation_type op, false_type)
         {
           if (op == clone_functor_tag) {
             // Clone the functor
@@ -377,7 +377,7 @@ namespace boost {
                 functor_manager_operation_type op, function_obj_tag)
         {
           manager(in_buffer, out_buffer, op,
-                  mpl::bool_<(function_allows_small_object_optimization<functor_type>::value)>());
+                  integral_constant<bool, (function_allows_small_object_optimization<functor_type>::value)>());
         }
 
         // For member pointers, we use the small-object optimization buffer.
@@ -385,7 +385,7 @@ namespace boost {
         manager(const function_buffer& in_buffer, function_buffer& out_buffer,
                 functor_manager_operation_type op, member_ptr_tag)
         {
-          manager(in_buffer, out_buffer, op, mpl::true_());
+          manager(in_buffer, out_buffer, op, true_type());
         }
 
       public:
@@ -427,7 +427,7 @@ namespace boost {
         // Function objects that fit in the small-object buffer.
         static inline void
         manager(const function_buffer& in_buffer, function_buffer& out_buffer,
-                functor_manager_operation_type op, mpl::true_)
+                functor_manager_operation_type op, true_type)
         {
           functor_manager_common<Functor>::manage_small(in_buffer,out_buffer,op);
         }
@@ -435,7 +435,7 @@ namespace boost {
         // Function objects that require heap allocation
         static inline void
         manager(const function_buffer& in_buffer, function_buffer& out_buffer,
-                functor_manager_operation_type op, mpl::false_)
+                functor_manager_operation_type op, false_type)
         {
           typedef functor_wrapper<Functor,Allocator> functor_wrapper_type;
 #if defined(BOOST_NO_CXX11_ALLOCATOR)
@@ -499,7 +499,7 @@ namespace boost {
                 functor_manager_operation_type op, function_obj_tag)
         {
           manager(in_buffer, out_buffer, op,
-                  mpl::bool_<(function_allows_small_object_optimization<functor_type>::value)>());
+                  integral_constant<bool, (function_allows_small_object_optimization<functor_type>::value)>());
         }
 
       public:
@@ -530,24 +530,24 @@ namespace boost {
 #ifdef BOOST_NO_SFINAE
       // These routines perform comparisons between a Boost.Function
       // object and an arbitrary function object (when the last
-      // parameter is mpl::bool_<false>) or against zero (when the
-      // last parameter is mpl::bool_<true>). They are only necessary
+      // parameter is false_type) or against zero (when the
+      // last parameter is true_type). They are only necessary
       // for compilers that don't support SFINAE.
       template<typename Function, typename Functor>
         bool
-        compare_equal(const Function& f, const Functor&, int, mpl::bool_<true>)
+        compare_equal(const Function& f, const Functor&, int, true_type)
         { return f.empty(); }
 
       template<typename Function, typename Functor>
         bool
         compare_not_equal(const Function& f, const Functor&, int,
-                          mpl::bool_<true>)
+                          true_type)
         { return !f.empty(); }
 
       template<typename Function, typename Functor>
         bool
         compare_equal(const Function& f, const Functor& g, long,
-                      mpl::bool_<false>)
+                      false_type)
         {
           if (const Functor* fp = f.template target<Functor>())
             return function_equal(*fp, g);
@@ -557,7 +557,7 @@ namespace boost {
       template<typename Function, typename Functor>
         bool
         compare_equal(const Function& f, const reference_wrapper<Functor>& g,
-                      int, mpl::bool_<false>)
+                      int, false_type)
         {
           if (const Functor* fp = f.template target<Functor>())
             return fp == g.get_pointer();
@@ -567,7 +567,7 @@ namespace boost {
       template<typename Function, typename Functor>
         bool
         compare_not_equal(const Function& f, const Functor& g, long,
-                          mpl::bool_<false>)
+                          false_type)
         {
           if (const Functor* fp = f.template target<Functor>())
             return !function_equal(*fp, g);
@@ -578,7 +578,7 @@ namespace boost {
         bool
         compare_not_equal(const Function& f,
                           const reference_wrapper<Functor>& g, int,
-                          mpl::bool_<false>)
+                          false_type)
         {
           if (const Functor* fp = f.template target<Functor>())
             return fp != g.get_pointer();
@@ -750,28 +750,28 @@ inline bool operator!=(detail::function::useless_clear_type*,
 template<typename Functor>
   inline bool operator==(const function_base& f, Functor g)
   {
-    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    typedef integral_constant<bool, (is_integral<Functor>::value)> integral;
     return detail::function::compare_equal(f, g, 0, integral());
   }
 
 template<typename Functor>
   inline bool operator==(Functor g, const function_base& f)
   {
-    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    typedef integral_constant<bool, (is_integral<Functor>::value)> integral;
     return detail::function::compare_equal(f, g, 0, integral());
   }
 
 template<typename Functor>
   inline bool operator!=(const function_base& f, Functor g)
   {
-    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    typedef integral_constant<bool, (is_integral<Functor>::value)> integral;
     return detail::function::compare_not_equal(f, g, 0, integral());
   }
 
 template<typename Functor>
   inline bool operator!=(Functor g, const function_base& f)
   {
-    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    typedef integral_constant<bool, (is_integral<Functor>::value)> integral;
     return detail::function::compare_not_equal(f, g, 0, integral());
   }
 #else
diff --git a/include/boost/function/function_template.hpp b/include/boost/function/function_template.hpp
index 81bacf7..e4ebb30 100644
--- a/include/boost/function/function_template.hpp
+++ b/include/boost/function/function_template.hpp
@@ -240,7 +240,7 @@ namespace boost {
       >
       struct BOOST_FUNCTION_GET_FUNCTION_INVOKER
       {
-        typedef typename mpl::if_c<(is_void<R>::value),
+        typedef typename conditional<(is_void<R>::value),
                             BOOST_FUNCTION_VOID_FUNCTION_INVOKER<
                             FunctionPtr,
                             R BOOST_FUNCTION_COMMA
@@ -261,7 +261,7 @@ namespace boost {
        >
       struct BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER
       {
-        typedef typename mpl::if_c<(is_void<R>::value),
+        typedef typename conditional<(is_void<R>::value),
                             BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER<
                             FunctionObj,
                             R BOOST_FUNCTION_COMMA
@@ -282,7 +282,7 @@ namespace boost {
        >
       struct BOOST_FUNCTION_GET_FUNCTION_REF_INVOKER
       {
-        typedef typename mpl::if_c<(is_void<R>::value),
+        typedef typename conditional<(is_void<R>::value),
                             BOOST_FUNCTION_VOID_FUNCTION_REF_INVOKER<
                             FunctionObj,
                             R BOOST_FUNCTION_COMMA
@@ -305,7 +305,7 @@ namespace boost {
        >
       struct BOOST_FUNCTION_GET_MEMBER_INVOKER
       {
-        typedef typename mpl::if_c<(is_void<R>::value),
+        typedef typename conditional<(is_void<R>::value),
                             BOOST_FUNCTION_VOID_MEMBER_INVOKER<
                             MemberPtr,
                             R BOOST_FUNCTION_COMMA
@@ -567,27 +567,27 @@ namespace boost {
         // Assign to a function object using the small object optimization
         template<typename FunctionObj>
         void
-        assign_functor(FunctionObj f, function_buffer& functor, mpl::true_) const
+        assign_functor(FunctionObj f, function_buffer& functor, true_type) const
         {
           new (reinterpret_cast<void*>(functor.data)) FunctionObj(f);
         }
         template<typename FunctionObj,typename Allocator>
         void
-        assign_functor_a(FunctionObj f, function_buffer& functor, Allocator, mpl::true_) const
+        assign_functor_a(FunctionObj f, function_buffer& functor, Allocator, true_type) const
         {
-          assign_functor(f,functor,mpl::true_());
+          assign_functor(f,functor,true_type());
         }
 
         // Assign to a function object allocated on the heap.
         template<typename FunctionObj>
         void
-        assign_functor(FunctionObj f, function_buffer& functor, mpl::false_) const
+        assign_functor(FunctionObj f, function_buffer& functor, false_type) const
         {
           functor.members.obj_ptr = new FunctionObj(f);
         }
         template<typename FunctionObj,typename Allocator>
         void
-        assign_functor_a(FunctionObj f, function_buffer& functor, Allocator a, mpl::false_) const
+        assign_functor_a(FunctionObj f, function_buffer& functor, Allocator a, false_type) const
         {
           typedef functor_wrapper<FunctionObj,Allocator> functor_wrapper_type;
 #if defined(BOOST_NO_CXX11_ALLOCATOR)
@@ -615,7 +615,7 @@ namespace boost {
         {
           if (!boost::detail::function::has_empty_target(boost::addressof(f))) {
             assign_functor(f, functor,
-                           mpl::bool_<(function_allows_small_object_optimization<FunctionObj>::value)>());
+                           integral_constant<bool, (function_allows_small_object_optimization<FunctionObj>::value)>());
             return true;
           } else {
             return false;
@@ -627,7 +627,7 @@ namespace boost {
         {
           if (!boost::detail::function::has_empty_target(boost::addressof(f))) {
             assign_functor_a(f, functor, a,
-                           mpl::bool_<(function_allows_small_object_optimization<FunctionObj>::value)>());
+                           integral_constant<bool, (function_allows_small_object_optimization<FunctionObj>::value)>());
             return true;
           } else {
             return false;