From 2d7137e7764ea0b08d48be30a5dea835878cd486 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Mon, 9 Oct 2023 03:19:06 +0200
Subject: [PATCH] Library: get rid of the invoker-helper

If we package all arguments together into a single tuple,
even including the member-function reference and the this-ptr
for the invokeThreadFunction(), which is the actual thread-functor,
then we can rely on std::make_from_tuple<T>(tuple), which implements
precisely the same hand-over via a std::index_sequence, as used by the
explicitly coded solution -- getting rid of some highly technical boilerplate
---
 src/lib/thread.hpp       | 31 ++++++++++++-------------------
 wiki/thinkPad.ichthyo.mm |  4 ++++
 2 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/src/lib/thread.hpp b/src/lib/thread.hpp
index 383bd9d54..11a664d86 100644
--- a/src/lib/thread.hpp
+++ b/src/lib/thread.hpp
@@ -134,8 +134,8 @@ namespace lib {
     using std::decay_t;
     using std::invoke_result_t;
     using std::is_constructible;
-    using std::index_sequence_for;
-    using std::index_sequence;
+    using std::make_from_tuple;
+    using std::tuple_cat;
     using std::is_same;
     using std::__or_;
     
@@ -344,28 +344,21 @@ namespace lib {
 
         
         
-        template<typename...INVO, size_t...idx>
-        static auto
-        buildLauncher_impl (tuple<INVO...>&& argCopy, index_sequence<idx...>)
-        {
-          return [invocation = move(argCopy)]
-                 (ThreadLifecycle& wrapper)
-                    {
-                      ASSERT (not wrapper.isLive());
-                      wrapper.threadImpl_
-                        = std::thread{&ThreadLifecycle::invokeThreadFunction<INVO...>
-                                     , &wrapper
-                                     , move(std::get<idx> (invocation))... };
-                    };
-        }
-        
         template<class...INVO>
         static auto
         buildLauncher (INVO&& ...args)
         {
           // materialise functor and arguments as copy, to be handed over into the new thread
-          return buildLauncher_impl (tuple<decay_t<INVO>...>{forward<INVO> (args)...}
-                                    ,index_sequence_for<INVO...>{});
+          tuple<decay_t<INVO>...> argCopy{forward<INVO> (args)...};
+          return [invocation = move(argCopy)]
+                 (ThreadLifecycle& wrapper)
+                    {
+                      auto threadArgs = tuple_cat (tuple{&ThreadLifecycle::invokeThreadFunction<INVO...>, &wrapper}
+                                                  ,move (invocation));
+                      ASSERT (not wrapper.isLive());
+                      wrapper.threadImpl_
+                        = make_from_tuple<std::thread> (threadArgs);
+                    };
         }
         
         
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 0ee17066d..a2ffe3593 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -65803,6 +65803,10 @@
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1696812791066" ID="ID_1789709297" MODIFIED="1696812798545" TEXT="Code sinnvoll anordnen">
 <icon BUILTIN="flag-yellow"/>
+<node CREATED="1696813183208" ID="ID_100161158" MODIFIED="1696813227123" TEXT="jetzt noch die invokeThreadFunctor-Memberfunktion mit in das Tupel packen..."/>
+<node CREATED="1696813171800" ID="ID_155742882" MODIFIED="1696813229500" TEXT="Ha! std::make_from_tuple">
+<icon BUILTIN="idea"/>
+</node>
 </node>
 </node>
 </node>