From 76fc4444379ec1fbd572a8f5a2d6a0118b419f20 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Sun, 2 Oct 2016 22:21:17 +0200
Subject: [PATCH] MutationMessage: implementation draft

---
 src/gui/ctrl/bus-controller.cpp      |  2 +-
 src/gui/ctrl/mutation-message.hpp    | 52 +++++++++++++++++++++++---
 tests/gui/abstract-tangible-test.cpp |  9 +++--
 tests/gui/test/mock-elm.hpp          |  9 +++++
 wiki/thinkPad.ichthyo.mm             | 55 ++++++++++++++++++++++++++++
 5 files changed, 117 insertions(+), 10 deletions(-)

diff --git a/src/gui/ctrl/bus-controller.cpp b/src/gui/ctrl/bus-controller.cpp
index 19c3add4d..91d64746c 100644
--- a/src/gui/ctrl/bus-controller.cpp
+++ b/src/gui/ctrl/bus-controller.cpp
@@ -73,7 +73,7 @@ namespace ctrl {
   }
   
   
-  MutationMessage::~MutationMessage() { }
+  diff_msg::Holder::~Holder() { }
   
   
   
diff --git a/src/gui/ctrl/mutation-message.hpp b/src/gui/ctrl/mutation-message.hpp
index b2a97721e..8c4f4bf50 100644
--- a/src/gui/ctrl/mutation-message.hpp
+++ b/src/gui/ctrl/mutation-message.hpp
@@ -52,12 +52,14 @@
 
 #include "lib/error.hpp"
 //#include "lib/symbol.hpp"
+#include "lib/opaque-holder.hpp"
 //#include "lib/util.hpp"
 //#include "lib/idi/entry-id.hpp"
 #include "lib/diff/diff-mutable.hpp"
 
 //#include <boost/noncopyable.hpp>
 //#include <utility>
+#include <utility>
 #include <string>
 
 
@@ -73,6 +75,42 @@ namespace ctrl{
 //  using lib::diff::GenNode;
   using std::string;
   
+  namespace diff_msg {
+    
+    class Holder
+      {
+      public:
+        virtual ~Holder();        ///< this is an interface
+        virtual void applyTo (lib::diff::DiffMutable&)   =0;
+        virtual string describe()  const                 =0;
+      };
+    
+    template<typename DIFF>
+    class Wrapped
+      : public Holder
+      {
+        DIFF diff_;
+        
+        virtual void
+        applyTo (lib::diff::DiffMutable& target)  override
+          {
+            UNIMPLEMENTED("how to embed a diff sequence and apply this to the target");
+          }
+        
+        virtual string
+        describe()  const override
+          {
+            UNIMPLEMENTED("string representation of diff/mutation messages");
+          }
+        
+      public:
+        Wrapped (DIFF&& diffSeq)
+          : diff_(std::move(diffSeq))
+          { }
+      };
+    
+    using Buffer = lib::InPlaceBuffer<Holder>;
+  }
   
   /**
    * Message on the UI-Bus holding an embedded diff sequence.
@@ -80,21 +118,25 @@ namespace ctrl{
    * to expose a TreeMutator, and then apply the embedded diff.
    */
   class MutationMessage
+    : public diff_msg::Buffer
     {
-    protected:
       
     public:
-      virtual ~MutationMessage();  ///< this is an interface
+      template<typename DIFF>
+      MutationMessage(DIFF&& diffSeq)
+        : diff_msg::Buffer{ embedType<diff_msg::Wrapped<DIFF>>()
+                          , std::move(diffSeq)}
+        { }
       
-      virtual void
+      void
       applyTo (lib::diff::DiffMutable& target)
         {
-          UNIMPLEMENTED("how to embed a diff sequence and apply this to the target");
+          access<diff_msg::Holder>()->applyTo(target);
         }
       
       operator string()  const
         {
-          UNIMPLEMENTED("string representation of diff/mutation messages");
+          return unConst(this)->access<diff_msg::Holder>()->describe();
         }
       
     protected:
diff --git a/tests/gui/abstract-tangible-test.cpp b/tests/gui/abstract-tangible-test.cpp
index 2acb90bd7..a855f65b5 100644
--- a/tests/gui/abstract-tangible-test.cpp
+++ b/tests/gui/abstract-tangible-test.cpp
@@ -76,6 +76,7 @@ using lib::diff::DataCap;
 using proc::control::Command;
 using proc::control::CommandDef;
 using gui::interact::InvocationTrail;
+using gui::ctrl::MutationMessage;
 
 
 
@@ -580,8 +581,8 @@ namespace test {
           MockElm rootMock("root");
           ID rootID = rootMock.getID();
           
-          rootMock["α"] = "Centauri";
-          CHECK ("Centauri" == rootMock["α"]);
+          rootMock.attrib["α"] = "Centauri";
+          CHECK ("Centauri" == rootMock.attrib["α"]);
           CHECK (isnil (rootMock.scope));
           
           
@@ -626,10 +627,10 @@ namespace test {
                << "\n───╼━━━━━━━━━╾────────────────"<<endl;
           
           CHECK (2 == rootMock.scope.size());                        // we've got two children now
-          CHECK (rootMock["α"] == "quadrant");                       // alpha attribute has been reassigned
+          CHECK (rootMock.attrib["α"] == "quadrant");                // alpha attribute has been reassigned
           CHECK (rootMock.scope[0].getID() == diffSrc.CHILD_1.idi);  // children have the expected IDs
           CHECK (rootMock.scope[1].getID() == diffSrc.CHILD_2.idi);
-          CHECK (rootMock.scope[1]["π"]    == "3.1415927");          // and the second child got attribute Pi
+          CHECK (rootMock.scope[1].attrib["π"]  == "3.1415927");     // and the second child got attribute Pi
         }
     };
   
diff --git a/tests/gui/test/mock-elm.hpp b/tests/gui/test/mock-elm.hpp
index 188898d52..3d04cff10 100644
--- a/tests/gui/test/mock-elm.hpp
+++ b/tests/gui/test/mock-elm.hpp
@@ -71,6 +71,8 @@
 #include "lib/util.hpp"
 
 #include <string>
+#include <vector>
+#include <map>
 
 
 namespace gui {
@@ -112,6 +114,7 @@ namespace test{
       string error_;
       
       
+      
       /* ==== Tangible interface ==== */
       
       virtual bool
@@ -295,6 +298,12 @@ namespace test{
       
       
       
+      /* ==== Attributes and mock children ==== */
+      
+      std::map<string, string> attrib;
+      std::vector<MockElm> scope;
+      
+      
       /* ==== Query/Verification API ==== */
       
       ID getID()  const
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 5bd00fa5d..cd9de3f0e 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -5590,6 +5590,61 @@
 <node CREATED="1475356059342" ID="ID_1039482059" MODIFIED="1475356066062" TEXT="wie wird Diff eingebettet">
 <icon BUILTIN="help"/>
 </node>
+<node CREATED="1475439403514" ID="ID_1619035258" MODIFIED="1475439643157" TEXT="Entscheidung">
+<icon BUILTIN="yes"/>
+<node CREATED="1475439416185" ID="ID_963854956" MODIFIED="1475439565484" TEXT="Builder-Funktion nicht sinnvoll">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ....denn dann m&#252;&#223;te der Benutzer die Mechanik sehr genau verstehen, und stets eine auto-Variable definieren.
+    </p>
+    <p>
+      Sinnvoll w&#228;re dieser Ansatz nur, wenn das UI-Bus-API eine MutationMessage const&amp; nehmen w&#252;rde,
+    </p>
+    <p>
+      denn dann k&#246;nnte man den Builder-Aufruf inline schreiben.
+    </p>
+    <p>
+      Da wir aber stets den Diff moven und dann iterieren, scheidet const&amp; aus
+    </p>
+    <p>
+      Und f&#252;r eine reine Ref erzeugt C++ niemals eine anonyme Instanz!
+    </p>
+  </body>
+</html>
+</richcontent>
+</node>
+<node CREATED="1475439429055" ID="ID_1383518557" MODIFIED="1475439634154" TEXT="also: embeded Buffer">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ...und diesen mit VTable best&#252;cken.
+    </p>
+    <p>
+      Daf&#252;r wird die &#228;u&#223;ere H&#252;lle non-virtual
+    </p>
+    <p>
+      und kann noncopyable gemacht werden..
+    </p>
+    <p>
+      Das erlaubt dem Benutzer, einfach zu schreiben
+    </p>
+    <p>
+      MutationMessage(blaBlubb())
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="ksmiletris"/>
+</node>
+<node CREATED="1475439436134" ID="ID_583247605" MODIFIED="1475439442228" TEXT="verwende InPlaceBuffer"/>
+</node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1475356066853" ID="ID_821643910" MODIFIED="1475356076468" TEXT="Problem: Puffergr&#xf6;&#xdf;e">
 <icon BUILTIN="flag-yellow"/>
 </node>