From 9378badf6bf629440f6e1a367be96777f6d8f074 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Sat, 30 Sep 2017 00:46:52 +0200
Subject: [PATCH] UI-Coordinates: integrate the initialisation split

...as developed in during the metaprogramming investigation
---
 src/lib/path-array.hpp   | 77 +++++++++++++++++++++++++++++++---------
 wiki/thinkPad.ichthyo.mm | 33 +++++++++++++++--
 2 files changed, 90 insertions(+), 20 deletions(-)

diff --git a/src/lib/path-array.hpp b/src/lib/path-array.hpp
index 9f3a73a5e..0fbb16993 100644
--- a/src/lib/path-array.hpp
+++ b/src/lib/path-array.hpp
@@ -49,10 +49,12 @@
 #include "lib/error.hpp"
 #include "lib/symbol.hpp"
 #include "lib/iter-adapter.hpp"
+#include "lib/meta/variadic-helper.hpp"
 #include "lib/util.hpp"
 
 //#include <boost/noncopyable.hpp>
 #include <algorithm>
+#include <utility>
 #include <string>
 #include <memory>
 #include <array>
@@ -61,6 +63,7 @@
 namespace lib {
   
 //  using std::unique_ptr;
+  using std::forward;
   using std::string;
   using lib::Literal;
   using util::unConst;
@@ -88,6 +91,7 @@ namespace lib {
             return reinterpret_cast<size_t&> (p[0]);
           }
         
+        
       public:
         Extension()
           : storage_{nullptr}
@@ -99,7 +103,8 @@ namespace lib {
           : storage_{new const char* [1 + sizeof...(ELMS)]}
           {
             size(storage_) = sizeof...(ELMS);
-            storage_[1] = {elms...};
+            std::initializer_list<const char*> lit{elms...};
+            std::copy (begin(lit),end(lit), storage_+1);
           }
           
        ~Extension()
@@ -161,6 +166,10 @@ namespace lib {
   
   
   
+  using meta::pickArg;
+  using meta::pickInit;
+  using meta::IndexSeq;
+  
   /**
    * Abstraction for path-like topological coordinates.
    * A sequence of Literal strings, with array-like access and
@@ -170,31 +179,59 @@ namespace lib {
   template<size_t chunk_size>
   class PathArray
     {
-      using LiteralArray = std::array<const char*, chunk_size>;
+      using Lit = const char*;
+      using LiteralArray = std::array<Lit, chunk_size>;
       
       LiteralArray elms_;
       con::Extension tail_;
       
+      /**
+       * @internal delegate ctor to place the initialiser arguments appropriately
+       * @remarks the two index sequences passed by pattern match determine which
+       *  arguments go to the inline array, and which go to heap allocated extension.
+       *  The inline array has fixed size an is thus filled with trailing `NULL` ptrs,
+       *  which is achieved with the help of meta::pickInit(). The con::Extension
+       *  is an embedded smart-ptr, which, when receiving additional tail arguments,
+       *  will place and manage them within a heap allocated array.
+       */
+      template<size_t...prefix, size_t...rest, typename...ARGS>
+      PathArray (IndexSeq<prefix...>
+                ,IndexSeq<rest...>
+                ,ARGS&& ...args)
+        : elms_{pickInit<prefix,Lit> (forward<ARGS>(args)...) ...}
+        , tail_{pickArg<rest>        (forward<ARGS>(args)...) ...}
+        {
+          this->normalise();
+        }
+      
+      /**
+       * @internal rebinding helper for building sequences of index numbers,
+       *  to route the initialiser arguments into the corresponding storage
+       *  - the leading (`chunk_size`) arguments go into the LiteralArray inline
+       *  - all the remaining arguments go into heap allocated extension storage
+       */
+      template<typename...ARGS>
+      struct Split
+        {
+          using Prefix = typename meta::BuildIndexSeq<chunk_size>::Ascending;
+          using Rest   = typename meta::BuildIdxIter<ARGS...>::template After<chunk_size>;
+        };
+        
     public:
       template<typename...ARGS>
       explicit
       PathArray (ARGS&& ...args)
-        : elms_{}
-        {
-          UNIMPLEMENTED ("initialise path array components");
-        }
+        : PathArray(typename Split<ARGS...>::Prefix()
+                   ,typename Split<ARGS...>::Rest()
+                   ,forward<ARGS> (args)...)
+        { }
       
-      PathArray (PathArray const& o)
-        : elms_(o.elms_)
-        {
-          UNIMPLEMENTED ("copy construct path array components");
-        }
-      
-      PathArray&
-      operator= (PathArray const& r)
-        {
-          UNIMPLEMENTED ("path array copy assignment");
-        }
+      PathArray(PathArray&&)                  = default;
+      PathArray(PathArray const&)             = default;
+      PathArray(PathArray& o)  : PathArray((PathArray const&)o) { }
+      PathArray& operator= (PathArray const&) = default;
+      PathArray& operator= (PathArray &&)     = default;
+                                               ////////////////////////TICKET #963  Forwarding shadows copy operations
       
       
       size_t
@@ -258,6 +295,12 @@ namespace lib {
         {
           UNIMPLEMENTED ("path implementation storage");
         }
+      
+      void
+      normalise()
+        {
+          UNIMPLEMENTED ("establish invariant");
+        }
     };
   
   
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 7ddc91a11..5ffe99778 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -3837,11 +3837,13 @@
 </node>
 <node CREATED="1506301421612" ID="ID_572376877" MODIFIED="1506301426568" TEXT="Meta-Problem">
 <icon BUILTIN="messagebox_warning"/>
-<node CREATED="1506301428698" ID="ID_1290675306" MODIFIED="1506301433910" TEXT="Parameter-Pack zerlegen">
+<node CREATED="1506301428698" ID="ID_1290675306" MODIFIED="1506723726199" TEXT="Parameter-Pack zerlegen">
+<icon BUILTIN="button_ok"/>
 <node CREATED="1506301435826" ID="ID_1852582857" MODIFIED="1506301447508" TEXT="ersten Teil in ein std::array"/>
 <node CREATED="1506301448288" ID="ID_1083459556" MODIFIED="1506301457058" TEXT="zweiten Teil rekursiv..."/>
 </node>
-<node CREATED="1506301468830" ID="ID_291609200" MODIFIED="1506301471937" TEXT="L&#xf6;sungen">
+<node CREATED="1506301468830" FOLDED="true" ID="ID_291609200" MODIFIED="1506723813858" TEXT="L&#xf6;sungen">
+<icon BUILTIN="button_ok"/>
 <node CREATED="1506301476836" ID="ID_1339982909" MODIFIED="1506302323712" TEXT="Stackoverflow">
 <icon BUILTIN="idea"/>
 <node CREATED="1506301629128" ID="ID_1265747852" LINK="https://stackoverflow.com/questions/14261183/how-to-make-generic-computations-over-heterogeneous-argument-packs-of-a-variadic" MODIFIED="1506301640408" TEXT="Param-Pack-Library"/>
@@ -3870,7 +3872,32 @@
 <node CREATED="1506301797721" ID="ID_1580459971" MODIFIED="1506301801941" TEXT="generell undurchsichtig"/>
 <node CREATED="1506301802865" ID="ID_1127036077" MODIFIED="1506301816915" TEXT="erfordert hohes Abstraktionsniveau"/>
 </node>
-<node CREATED="1506301834493" ID="ID_52512330" MODIFIED="1506301846055" TEXT="selber schreiben anhand Beispiel"/>
+<node COLOR="#338800" CREATED="1506301834493" ID="ID_52512330" MODIFIED="1506723706338" TEXT="selber schreiben anhand Beispiel">
+<icon BUILTIN="button_ok"/>
+<node CREATED="1506723689710" ID="ID_454128552" MODIFIED="1506723762301" TEXT="Mini-Framework">
+<icon BUILTIN="button_ok"/>
+</node>
+<node CREATED="1506723694704" ID="ID_649123940" MODIFIED="1506723759877" TEXT="meta::pickArg">
+<icon BUILTIN="button_ok"/>
+</node>
+<node CREATED="1506723699774" ID="ID_748812841" MODIFIED="1506723757331" TEXT="meta::pickInit">
+<icon BUILTIN="button_ok"/>
+</node>
+<node CREATED="1506723746120" ID="ID_154958112" MODIFIED="1506723790105" TEXT="unit-test dazu">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      VariadicArgumentPicker_test
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="button_ok"/>
+</node>
+</node>
 </node>
 </node>
 </node>