[libsigc++2/variadic_bind3: 34/45] hide_functor: Make this fully variadic.

[Murray Cumming <murrayc src gnome org>]

commit abd94310882251f2e811916398aef2c6305bb860
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Jan 14 17:37:59 2016 +0100

    hide_functor: Make this fully variadic.

 sigc++/adaptors/macros/hide.h.m4 |  135 ++++++++++++++++---------------------
 1 files changed, 58 insertions(+), 77 deletions(-)
---
diff --git a/sigc++/adaptors/macros/hide.h.m4 b/sigc++/adaptors/macros/hide.h.m4
index b37cadc..3ed7508 100644
--- a/sigc++/adaptors/macros/hide.h.m4
+++ b/sigc++/adaptors/macros/hide.h.m4
@@ -25,77 +25,6 @@ ifelse($1,0,,$1)ifelse($1,0,[last],$1,1,[st],$1,2,[nd],$1,3,[rd],[th])[]dnl
 ])])dnl
 ])dnl end HIDE_OPERATOR
 
-define([HIDE_FUNCTOR],[dnl
-ifelse($1,1,[#ifndef DOXYGEN_SHOULD_SKIP_THIS
-],)dnl Include only the first two template specializations in the documentation. ($1 = -1..CALL_SIZE-1)
-/** Adaptor that adds a dummy parameter to the wrapped functor.
- * This template specialization ignores the value of the ORDINAL(eval($1+1)) parameter in operator()().
- *
- * @ingroup hide
- */
-template <class T_functor>
-struct hide_functor <$1, T_functor> : public adapts<T_functor>
-{
-  typedef typename adapts<T_functor>::adaptor_type adaptor_type;
-  typedef typename adaptor_type::result_type  result_type;
-
-  /** Invokes the wrapped functor, ignoring the ORDINAL($1) argument.dnl
-   * @param _A_a Arguments to be passed on to the functor, apart from the ORDINAL($1) argument.
-   * @return The return value of the functor invocation.
-   */
-  template <class... T_arg>
-  decltype(auto)
-  operator()(T_arg... _A_a)
-    {
-       constexpr auto size = sizeof...(T_arg);
-       constexpr auto index_ignore = ($1 == -1 ? size - 1 : $1);
-       const auto t = std::make_tuple(_A_a...);
-
-       const auto t_start = tuple_start<index_ignore>(t);
-       const auto t_end = tuple_end<size - index_ignore - 1>(t);
-       auto t_used = std::tuple_cat(t_start, t_end); //TODO: Let this be const?
-
-       //This is so we can specify a particular instantiation of the functor's
-       //operator().
-       //TODO: Avoid this if it no longer necessary.
-       using t_type = std::tuple<type_trait_pass_t<T_arg>...>;
-       using t_type_start = typename tuple_type_start<t_type, index_ignore>::type;
-       using t_type_end = typename tuple_type_end<t_type, size - index_ignore - 1>::type;
-       using t_type_used = typename tuple_type_cat<t_type_start, t_type_end>::type;
-
-       constexpr auto size_used = size - 1;
-
-       //TODO: Remove these? They are just here as a sanity check.
-       static_assert(std::tuple_size<t_type_used>::value == size_used, "Unexpected t_type_used size.");
-       static_assert(std::tuple_size<decltype(t_used)>::value == size_used, "Unexpected t_used size.");
-
-       const auto seq = std::make_index_sequence<size_used>();
-       return call_functor_operator_parentheses<t_type_used>(t_used, seq);
-    }
-
-  /** Constructs a hide_functor object that adds a dummy parameter to the passed functor.
-   * @param _A_func Functor to invoke from operator()().
-   */
-  explicit hide_functor(const T_functor& _A_func)
-    : adapts<T_functor>(_A_func)
-    {}
-
-private:
-  //TODO_variadic: Replace this with std::experimental::apply() if that becomes standard
-  //C++, or add our own implementation, to avoid code duplication.
-  template<class T_tuple_specific, class T_tuple, std::size_t... Is>
-  decltype(auto)
-  call_functor_operator_parentheses(T_tuple& tuple,
-    std::index_sequence<Is...>)
-  {
-    return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<typename std::tuple_element<Is, 
T_tuple_specific>::type...>(std::get<Is>(tuple)...);
-  }
-};
-ifelse($1,eval(CALL_SIZE-1),[#endif // DOXYGEN_SHOULD_SKIP_THIS
-],)dnl Include only the first two template specializations in the documentation. ($1 = -1..CALL_SIZE-1)
-
-])dnl end HIDE_FUNCTOR
-
 divert(0)dnl
 _FIREWALL([ADAPTORS_HIDE])
 #include <sigc++/adaptors/adaptor_trait.h>
@@ -151,6 +80,7 @@ namespace sigc {
  * @ingroup adaptors
  */
 
+
 /** Adaptor that adds a dummy parameter to the wrapped functor.
  * Use the convenience function sigc::hide() to create an instance of sigc::hide_functor.
  *
@@ -162,13 +92,64 @@ namespace sigc {
  * @ingroup hide
  */
 template <int I_location, class T_functor>
-#ifndef DOXYGEN_SHOULD_SKIP_THIS
-struct hide_functor;
-#else
-struct hide_functor {};
-#endif
+struct hide_functor : public adapts<T_functor>
+{
+  typedef typename adapts<T_functor>::adaptor_type adaptor_type;
+  typedef typename adaptor_type::result_type  result_type;
+
+  /** Invokes the wrapped functor, ignoring the argument at index @e I_location (0-indexed).
+   * @param _A_a Arguments to be passed on to the functor, apart from the ignored argument.
+   * @return The return value of the functor invocation.
+   */
+  template <class... T_arg>
+  decltype(auto)
+  operator()(T_arg... _A_a)
+    {
+       constexpr auto size = sizeof...(T_arg);
+       constexpr auto index_ignore = (I_location == -1 ? size - 1 : I_location);
+       const auto t = std::make_tuple(_A_a...);
+
+       const auto t_start = tuple_start<index_ignore>(t);
+       const auto t_end = tuple_end<size - index_ignore - 1>(t);
+       auto t_used = std::tuple_cat(t_start, t_end); //TODO: Let this be const?
+
+       //This is so we can specify a particular instantiation of the functor's
+       //operator().
+       //TODO: Avoid this if it no longer necessary.
+       using t_type = std::tuple<type_trait_pass_t<T_arg>...>;
+       using t_type_start = typename tuple_type_start<t_type, index_ignore>::type;
+       using t_type_end = typename tuple_type_end<t_type, size - index_ignore - 1>::type;
+       using t_type_used = typename tuple_type_cat<t_type_start, t_type_end>::type;
+
+       constexpr auto size_used = size - 1;
+
+       //TODO: Remove these? They are just here as a sanity check.
+       static_assert(std::tuple_size<t_type_used>::value == size_used, "Unexpected t_type_used size.");
+       static_assert(std::tuple_size<decltype(t_used)>::value == size_used, "Unexpected t_used size.");
+
+       const auto seq = std::make_index_sequence<size_used>();
+       return call_functor_operator_parentheses<t_type_used>(t_used, seq);
+    }
+
+  /** Constructs a hide_functor object that adds a dummy parameter to the passed functor.
+   * @param _A_func Functor to invoke from operator()().
+   */
+  explicit hide_functor(const T_functor& _A_func)
+    : adapts<T_functor>(_A_func)
+    {}
+
+private:
+  //TODO_variadic: Replace this with std::experimental::apply() if that becomes standard
+  //C++, or add our own implementation, to avoid code duplication.
+  template<class T_tuple_specific, class T_tuple, std::size_t... Is>
+  decltype(auto)
+  call_functor_operator_parentheses(T_tuple& tuple,
+    std::index_sequence<Is...>)
+  {
+    return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<typename std::tuple_element<Is, 
T_tuple_specific>::type...>(std::get<Is>(tuple)...);
+  }
+};
 
-FOR(-1,eval(CALL_SIZE-1),[[HIDE_FUNCTOR(%1)]])dnl
 
 #ifndef DOXYGEN_SHOULD_SKIP_THIS
 //template specialization of visitor<>::do_visit_each<>(action, functor):