Invocation: demonstrate complete usage cycle of extension block

In `NodeFeed_test`...
Demonstrate the base mechanism of creating a ''Param Spec'' with a
functor-definition for each parameter. This can then later be used to
invoke those functors and materialise the results into a data tuple,
and this data tuple can be linked into the TurnoutSystem, so that
the parameter values can be accessed type-safe with getter-functors.

src/lib/hetero-data.hpp

@@ -110,6 +110,8 @@ namespace lib {
       
       template<typename SPEC>
       void linkInto (HeteroData<SPEC>&);
+      template<typename SPEC>
+      void detachFrom (HeteroData<SPEC>&);
       
       template<size_t slot> auto& get() noexcept { return std::get<slot>(*this); }
       template<typename X>  auto& get() noexcept { return std::get<X>(*this);    }
@@ -143,7 +145,8 @@ namespace lib {
       _Tail&
       accessTail()
         {
-          REQUIRE (Frame::next, "HeteroData storage logic broken: follow-up extent not yet allocated");
+          if (Frame::next == nullptr) // Halt system by breaking noexcept
+            throw lumiera::error::Fatal{"HeteroData storage logic broken: follow-up extent not(yet) allocated"};
           return * reinterpret_cast<_Tail*> (Frame::next);
         }
       
@@ -341,6 +344,32 @@ namespace lib {
              , segments);
       return last->next;
     }
+    
+    /**
+     * @internal detach the HeteroData-chain at the link to the given chainBlock.
+     *  This enables some additional data sanity, because the internal chain can
+     *  thus be severed when an extension data block is known to go out of scope.
+     *  If somehow a store accessor is used after that point, the system will
+     *  be halted when attempting to navigate to the (now defunct) data block.
+     */
+    inline void
+    checkedDetach (size_t segments, StorageLoc* seg, void* chainBlock)
+    {
+      REQUIRE(seg);
+      while (segments and seg->next)
+        if (segments == 1 and seg->next == chainBlock)
+          {
+            seg->next = nullptr;
+            return;
+          }
+        else
+          {
+            seg = seg->next;
+            --segments;
+          }
+      NOTREACHED ("Failure to detach a data segment from HeteroData: "
+                  "assumed type structure does not match real connectivity");
+    }
   }//(End)helper
   
   
@@ -369,6 +398,16 @@ namespace lib {
     ENSURE (lastLink == nullptr);
     lastLink = this;
   }
+  
+  /** cleanly detach this storage frame from the HeteroData prefix-chain. */
+  template<size_t seg, typename...DATA>
+  template<typename SPEC>
+  inline void
+  StorageFrame<seg,DATA...>::detachFrom (HeteroData<SPEC>& prefixChain)
+  {
+    StorageLoc*  firstSeg = reinterpret_cast<StorageLoc*> (&prefixChain);
+    checkedDetach (seg, firstSeg, this);
+  }
 }// namespace lib
 
 

src/steam/engine/turnout-system.hpp

@@ -67,10 +67,6 @@ namespace engine {
            };
       
     private:
-      template<class SPEC, size_t idx>
-      using Accessor = typename lib::HeteroData<SPEC>::template Accessor<idx>;
-      
-      
       FrontBlock invoParam_;
       
     public:
@@ -90,19 +86,31 @@ namespace engine {
           return invoParam_.get<SLOT_KEY>();
         }
       
-      template<class SPEC, size_t idx>
+      template<class ACC>
       auto&
-      get (Accessor<SPEC,idx> const& getter)
+      get (ACC const& getter)
         {
           return getter.get (invoParam_);
         }
       
+      /** attach an extension block with further parameters
+       *  as HeteroData-chain to the embedded FrontBlock
+       * @note structural properties must match, which
+       *       is ensured when using a ParamBuildSpec.
+       */
       template<class CHAIN>
       void
       attachChainBlock (CHAIN& chainBlock)
         {
           chainBlock.linkInto (invoParam_);
         }
+      
+      template<class CHAIN>
+      void
+      detachChainBlock (CHAIN& chainBlock)
+        {
+          chainBlock.detachFrom (invoParam_);
+        }
     };
     
     

tests/core/steam/engine/node-feed-test.cpp

@@ -27,6 +27,7 @@
 #include "steam/asset/meta/time-grid.hpp"
 #include "lib/several-builder.hpp"
 #include "lib/time/timecode.hpp"
+#include "lib/test/test-helper.hpp"
 #include "lib/test/diagnostic-output.hpp"/////////////////////TODO
 //#include "lib/util.hpp"
 
@@ -36,6 +37,8 @@ using lib::Several;
 using lib::makeSeveral;
 using lib::time::Time;
 using lib::time::FSecs;
+using lib::time::FrameNr;
+using lib::test::showType;
 
 
 namespace steam {
@@ -44,7 +47,6 @@ namespace test  {
   
   
   
-  
   /************************************************************************//**
    * @test demonstrate how to feed data into, through and out of render nodes.
    */
@@ -53,6 +55,7 @@ namespace test  {
       virtual void
       run (Arg)
         {
+          seedRand();
           feedParam();
           feedParamNode();
           UNIMPLEMENTED ("render node pulling source data from vault");
@@ -105,36 +108,73 @@ namespace test  {
           result.release();
         }
       
-      /** @test create extended parameter data for use in recursive Node invocation */
+      
+      /** @test create extended parameter data for use in recursive Node invocation.
+       *      - demonstrate the mechanism of param-functor invocation,
+       *        and how a Param-Spec is built to create and hold those functors
+       *      - then instantiate an actual TurnoutSystem, as is done for a Node invocation,
+       *        with an embedded »absolute nominal time« parameter value
+       *      - can then invoke the param-functors and materialise results into a Param-Data-Block
+       *      - which then can be linked internally to be reachable through the TurnoutSystem
+       *      - other code further down the call-stack can thus access those parameter values.
+       *      - The second part of the test uses the same scheme embedded into a Param(Agent)Node
+       */
       void
       feedParamNode()
         {
           steam::asset::meta::TimeGrid::build("grid_sec", 1);
           
+          // Parameter-functor based on time-quantisation into a 1-seconds-grid
           auto fun1 = [](TurnoutSystem& turSys)
                         {
-                          return lib::time::FrameNr::quant (turSys.getNomTime(), "grid_sec");
+                          return FrameNr::quant (turSys.getNomTime(), "grid_sec");
                         };
           
+          // The Param-Spec is used to coordinate type-safe access
+          // and also is used as a blueprint for building a Param(Agent)Node
           auto spec = buildParamSpec()
                         .addValSlot (LIFE_AND_UNIVERSE_4EVER)
                         .addSlot (move (fun1))
                         ;
-          using Spec = decltype(spec);
-SHOW_TYPE(Spec)
-SHOW_TYPE(Spec::ParamTup)
           
-          TurnoutSystem turnoutSys{Time{FSecs(5,2)}};
+          // The implied type of the parameter-tuple to generate
+          using ParamTup = decltype(spec)::ParamTup;
+          CHECK (showType<ParamTup>() == "tuple<uint, long>"_expect);
+          
+          // can now store accessor-functors for later use....
+          auto acc0 = spec.slot<0>().makeAccessor();
+          auto acc1 = spec.slot<1>().makeAccessor();
+          
+          // drive test with a random »nominal Time« <10s with ms granularity
+          Time nomTime{rani(10'000),0};
+          TurnoutSystem turnoutSys{nomTime};
+          // can now immediately invoke the embedded parameter-functors
           auto v0 = spec.slot<0>().invokeParamFun (turnoutSys);
           auto v1 = spec.slot<1>().invokeParamFun (turnoutSys);
-SHOW_EXPR(v0)
+          CHECK (v0 == LIFE_AND_UNIVERSE_4EVER);                      // ◁————————— the first paramFun yields the configured fixed value
-SHOW_EXPR(v1)
+          CHECK (v1 == FrameNr::quant (nomTime, "grid_sec"));         // ◁————————— the second paramFun accesses the time in TurnoutSystem
+
+          {  //  Now build an actual storage block in local scope,
+            //   thereby invoking the embedded parameter-functors...
+            auto paramBlock = spec.buildParamDataBlock (turnoutSys);
+            // Values are now materialised into paramBlock
+            CHECK (v0 == paramBlock.get<0>());
+            CHECK (v1 == paramBlock.get<1>());
+            
+            // link this extension block into the parameter-chain in TurnoutSystem
+            turnoutSys.attachChainBlock(paramBlock);
+            
+            // can now access the parameter values through the TurnoutSystem as front-End
+            CHECK (v0 == spec.slot<0>().getParamVal (turnoutSys));
+            CHECK (v1 == spec.slot<1>().getParamVal (turnoutSys));
+            // and can also use the accessor-functors stored above
+            CHECK (v0 == turnoutSys.get(acc0));
+            CHECK (v1 == turnoutSys.get(acc1));
+            
+            // should detach extension block before leaving scope
+            turnoutSys.detachChainBlock(paramBlock);
+          }
 
-          auto paramBlock = spec.buildParamDataBlock (turnoutSys);
-SHOW_EXPR(paramBlock)
-SHOW_EXPR(paramBlock.get<0>())
-SHOW_EXPR(paramBlock.get<1>())
-          
           TODO ("implement a simple Builder for ParamAgent-Node");
           TODO ("then use both together to demonstrate a param data feed here");
         }

wiki/thinkPad.ichthyo.mm

@@ -82336,8 +82336,19 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <node CREATED="1735353775789" ID="ID_1394846816" MODIFIED="1735353797045" TEXT="dazu ist ein Funktor-Typ definiert"/>
 <node CREATED="1735353798274" ID="ID_1422658744" MODIFIED="1735353856467" TEXT="und ein Accessor-Typ">
 <node CREATED="1735353948999" ID="ID_1107757772" MODIFIED="1735353956728" TEXT="dieser findet zum Slot zur&#xfc;ck"/>
-<node CREATED="1735353970175" ID="ID_542964897" MODIFIED="1735353992387" TEXT="und ist eine Erweiterung der HeteroData-Accessoren">
+<node CREATED="1735353970175" ID="ID_542964897" MODIFIED="1735519560792" TEXT="und ist ein HeteroData-Accessor"/>
-<node CREATED="1735353994703" ID="ID_755528962" MODIFIED="1735354004015" TEXT="vielleicht gar keine Erweiterung?"/>
+<node CREATED="1735519565352" ID="ID_646241396" MODIFIED="1735519667848" TEXT="mit dem TurnoutSystem als Front-Block">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      Das hei&#223;t, hier haben wir immer einen festen Satz an Parametern, die stets im TurnoutSystem eingebettet vorliegen; diese k&#246;nnen aber als HeteroData-Chain erweitert werden um die Bl&#246;cke, die wir &#252;ber eine (oder eine Kette von) ParamBuildSpec erzeugen
+    </p>
+  </body>
+</html>
+</richcontent>
 </node>
 </node>
 </node>
@@ -94180,8 +94191,9 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <linktarget COLOR="#4033e3" DESTINATION="ID_348960119" ENDARROW="Default" ENDINCLINATION="-2228;-103;" ID="Arrow_ID_1086551966" SOURCE="ID_1769136387" STARTARROW="None" STARTINCLINATION="1977;97;"/>
 <linktarget COLOR="#ff6936" DESTINATION="ID_348960119" ENDARROW="Default" ENDINCLINATION="-641;1944;" ID="Arrow_ID_1163958018" SOURCE="ID_311704401" STARTARROW="None" STARTINCLINATION="1383;132;"/>
 <icon BUILTIN="pencil"/>
-<node CREATED="1735416170297" ID="ID_736958022" MODIFIED="1735416236279" TEXT="brauche ParamBuildSpec">
+<node BACKGROUND_COLOR="#c8c0b6" COLOR="#435e98" CREATED="1735416170297" ID="ID_736958022" MODIFIED="1735519479807" TEXT="brauche ParamBuildSpec">
 <linktarget COLOR="#bb1f2e" DESTINATION="ID_736958022" ENDARROW="Default" ENDINCLINATION="-25;-162;" ID="Arrow_ID_44922252" SOURCE="ID_1577179744" STARTARROW="None" STARTINCLINATION="32;153;"/>
+<icon BUILTIN="yes"/>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1735422554816" ID="ID_197118422" MODIFIED="1735438575232" TEXT="Aufgabe: schrittweise aufbaubar">
 <icon BUILTIN="flag-yellow"/>
 <node CREATED="1735422591091" ID="ID_1649575055" MODIFIED="1735422735480" TEXT="Diskrepanz zu den HeteroData Chain-Blocks">
@@ -94235,8 +94247,8 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <node CREATED="1735486938666" ID="ID_1675979650" MODIFIED="1735487816128" TEXT="also direkt anwendbar auf&apos;s Turnout-System"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1735427341106" ID="ID_29906476" MODIFIED="1735427368610" TEXT="L&#xf6;sung aufbauen...">
+<node COLOR="#338800" CREATED="1735427341106" ID="ID_29906476" MODIFIED="1735519449554" TEXT="L&#xf6;sung aufbauen...">
-<icon BUILTIN="pencil"/>
+<icon BUILTIN="button_ok"/>
 <node CREATED="1735427377686" ID="ID_1047293090" MODIFIED="1735427389228" TEXT="Typisierung">
 <node CREATED="1735427448052" ID="ID_1835841396" MODIFIED="1735427511976" TEXT="mu&#xdf; komplett explizit sein">
 <richcontent TYPE="NOTE"><html>
@@ -94298,8 +94310,8 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <linktarget COLOR="#637488" DESTINATION="ID_870944737" ENDARROW="Default" ENDINCLINATION="310;0;" ID="Arrow_ID_1871378220" SOURCE="ID_1331974543" STARTARROW="None" STARTINCLINATION="145;9;"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1735438595508" ID="ID_696254160" MODIFIED="1735438784764" TEXT="Implementierung">
+<node COLOR="#338800" CREATED="1735438595508" ID="ID_696254160" MODIFIED="1735519446480" TEXT="Implementierung">
-<icon BUILTIN="pencil"/>
+<icon BUILTIN="button_ok"/>
 <node COLOR="#338800" CREATED="1735438607044" ID="ID_1948837984" MODIFIED="1735438628651" TEXT="Builder-Anker: buildParamSpec()">
 <icon BUILTIN="button_ok"/>
 </node>
@@ -94311,13 +94323,13 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
 <node CREATED="1735438678865" ID="ID_548533062" MODIFIED="1735438686677" TEXT="&#xe4;hnlich wie f&#xfc;r die FeedManifold"/>
 <node CREATED="1735438687997" ID="ID_283878162" MODIFIED="1735438699784" TEXT="verwendet lib::meta::ElmTypes :: Apply"/>
 </node>
-<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1735438707680" ID="ID_1085577180" MODIFIED="1735438715228" TEXT="Zugriffs-Slot">
+<node COLOR="#338800" CREATED="1735438707680" ID="ID_1085577180" MODIFIED="1735519443885" TEXT="Zugriffs-Slot">
-<icon BUILTIN="pencil"/>
+<icon BUILTIN="button_ok"/>
 <node COLOR="#338800" CREATED="1735438717070" ID="ID_1429780349" MODIFIED="1735438724209" TEXT="jeweiligen Funktor aufrufen">
 <icon BUILTIN="button_ok"/>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1735438726120" ID="ID_1670785950" MODIFIED="1735438739642" TEXT="Daten-Accessor konstruieren">
+<node COLOR="#338800" CREATED="1735438726120" ID="ID_1670785950" MODIFIED="1735519440292" TEXT="Daten-Accessor konstruieren">
-<icon BUILTIN="flag-yellow"/>
+<icon BUILTIN="button_ok"/>
 <node CREATED="1735487309329" ID="ID_1516453754" MODIFIED="1735487326656" TEXT="Bassis sind Accessoren auf HeteroData"/>
 <node CREATED="1735489834862" ID="ID_1311598461" MODIFIED="1735489845645" TEXT="mu&#xdf; dazu den Chain-Block-Typ konstruieren">
 <node CREATED="1735489850973" ID="ID_1621449411" MODIFIED="1735489863415" TEXT="aus dem Anker-Typ :: Chain"/>