Parameter: first rough-edged implementation of value access

...as expected, the first attempt to walk the full access path unveils a host of problematic aspects in the design...
2026-09-02 01:27:27 +02:00 · 2026-09-02 01:27:27 +02:00 · 2467405c25
commit 2467405c25
parent a5f1709bff
5 changed files with 115 additions and 13 deletions
--- a/src/lib/par/disposition.hpp
+++ b/src/lib/par/disposition.hpp
@ -44,6 +44,15 @@ namespace par {
    : public Domain
    {
    public:
+      template<typename X>
+      X extract()  const;
+      
+      template<typename X>
+      void setVal (X);
+      
+    private:
+      template<typename X>
+      bool isBaseDomainMatch()  const;
    };
  
  
@ -66,6 +75,58 @@ namespace par {
        { }
    };
  
+  template<typename X>
+  using FullDomain = BaseDomain<X, Disposition>;
+  
+  
+  
+  template<typename X>
+  X
+  Disposition::extract()  const
+  {
+    X result; // RVO
+    
+    if (isBaseDomainMatch<X>())
+      { // short-circuit by direct force-cast
+        retrieveInto (asValBuff (result));
+      }
+    else
+      { // run full type-conversion double-dispatch
+        uint64_t valueBuffer; /////////////////////////////////////////////////OOO need a way to get a suitably sized intermediary buffer (without heap-allocation)
+        this->retrieveInto (asValBuff(valueBuffer));
+        
+        FullDomain<X> targetDomain;
+        this->transferTo (asValBuff(valueBuffer), targetDomain, asValBuff(result));
+      }
+    return result;
+  }
+  
+  
+  template<typename X>
+  void
+  Disposition::setVal (X changedVal)
+  {
+    if (isBaseDomainMatch<X>())
+      { // short-circuit by direct force-cast
+        setValFrom (asValBuff (changedVal));
+      }
+    else
+      { // run full type-conversion double-dispatch
+        uint64_t valueBuffer; /////////////////////////////////////////////////OOO need a way to get a suitably sized intermediary buffer (without heap-allocation)
+        FullDomain<X> targetDomain;
+        
+        targetDomain.transferTo (asValBuff(changedVal), *this, asValBuff(valueBuffer));
+        this->setValFrom (asValBuff(valueBuffer));
+      }
+  }
+  
+  
+  template<typename X>
+  bool
+  Disposition::isBaseDomainMatch()  const
+  {
+    return false; /////////////////////////OOO running into a dead end here? how can we possibly access a type tag marker without indirection??
+  }
  
  
 }} // namespace lib::par
--- a/src/lib/par/domain.hpp
+++ b/src/lib/par/domain.hpp
@ -108,7 +108,7 @@ namespace par {
      virtual ~Domain();  ///< this is an interface
      
      virtual void applyLimit (ValBuff&)  =0;
-      virtual void transferTo (ValBuff const& source, Domain& targetDomain, ValBuff& target) =0;
+      virtual void transferTo (ValBuff const& source, Domain& targetDomain, ValBuff& target)  const  =0;
      
    protected:
    };
--- a/src/lib/par/param-type.hpp
+++ b/src/lib/par/param-type.hpp
@ -74,7 +74,7 @@ _Pragma("GCC diagnostic ignored \"-Woverloaded-virtual\"")
    {
    public:
      void applyLimit (ValBuff&)  override;
-      void transferTo (ValBuff const& source, Domain& targetDomain, ValBuff& target) override;
+      void transferTo (ValBuff const& source, Domain& targetDomain, ValBuff& target)  const override;
    };
  
  
@ -207,7 +207,7 @@ _Pragma("GCC diagnostic pop")
  
  template<typename VAL, class IFA>
  inline void
-  BaseDomain<VAL,IFA>::transferTo (ValBuff const& source, Domain& targetDomain, ValBuff& target)
+  BaseDomain<VAL,IFA>::transferTo (ValBuff const& source, Domain& targetDomain, ValBuff& target)  const
  {
    targetDomain.conform (target, asValue<VAL> (source));
    targetDomain.applyLimit (target);
--- a/src/lib/par/parameter.hpp
+++ b/src/lib/par/parameter.hpp
@ -32,6 +32,7 @@
 #include "lib/par/disposition.hpp"
 #include "lib/polymorphic-value.hpp"
 #include "lib/meta/typelist-util.hpp"
+#include "lib/util.hpp"

 #include <utility>

@ -46,6 +47,8 @@ namespace par {
    using ParamContainer = PolymorphicValue<ParameterImplAPI, BUFF_SIZ, CopySupportMarker>;
  }
  
+  using util::unConst;
+  
  
  
  /**
@ -60,7 +63,7 @@ namespace par {
      class Builder;
      
      template<typename VAL>
-      VAL getVal();
+      VAL getVal() const;
      
      template<typename VAL>
      void setVal (VAL&&);
@ -119,9 +122,9 @@ namespace par {
  
  template<typename VAL>
  VAL
-  Parameter::getVal()
+  Parameter::getVal()  const
    {
-      UNIMPLEMENTED ("extract the »value«, possibly applying suitable type conversions");
+      return unConst(this)->getPayload().extract<VAL>();
    }
  
  
@ -129,7 +132,7 @@ namespace par {
  void
  Parameter::setVal (VAL&& changedVal)
    {
-      UNIMPLEMENTED ("apply suitable type conversions and clamping, then transfer the new value into the Provision interface");
+      getPayload().setVal (changedVal);
    }
  
  
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@ -82955,7 +82955,7 @@
 </html></richcontent>
 </node>
 </node>
-<node CREATED="1783092344401" ID="ID_723247866" MODIFIED="1783092356166" TEXT="ParamType">
+<node CREATED="1783092344401" ID="ID_723247866" MODIFIED="1788306366293" TEXT="Provision">
 <node CREATED="1783092477119" ID="ID_1734714581" MODIFIED="1783092481906" TEXT="Interfaface">
 <node CREATED="1783092482966" ID="ID_1196126403" MODIFIED="1783092486026" TEXT="virtuell"/>
 <node CREATED="1783092486716" ID="ID_1507254773" MODIFIED="1783092489572" TEXT="generisch">
@ -82987,8 +82987,17 @@
 </node>
 </node>
 </node>
-<node CREATED="1783101507062" ID="ID_1298955481" MODIFIED="1783101521840" TEXT="Header: lib/par/param-type.hpp|cpp">
-<node CREATED="1783101523306" ID="ID_1764325281" MODIFIED="1783172855177" TEXT="hier auch die Type-Registry"/>
+<node CREATED="1783101507062" ID="ID_1298955481" MODIFIED="1788306389082" TEXT="Header....">
+<node CREATED="1788306396605" ID="ID_1497186410" MODIFIED="1788306410252" TEXT="lib/par/provision.hpp">
+<node CREATED="1788306414146" HGAP="71" ID="ID_833702080" MODIFIED="1788306467320" TEXT="Buffer-Zugriffs-Mechanik" VSHIFT="2">
+<font NAME="SansSerif" SIZE="10"/>
+</node>
+</node>
+<node CREATED="1788306390020" ID="ID_1994320454" MODIFIED="1788306392775" TEXT="lib/par/param-type.hpp|cpp">
+<node CREATED="1783101523306" HGAP="29" ID="ID_1764325281" MODIFIED="1788306464746" TEXT="hier auch die Type-Registry" VSHIFT="2">
+<font NAME="SansSerif" SIZE="10"/>
+</node>
+</node>
 </node>
 </node>
 <node CREATED="1783097554556" ID="ID_1339731751" MODIFIED="1783097566222" TEXT="Domain">
@ -84487,7 +84496,8 @@
 <node CREATED="1788293586698" ID="ID_1746668987" MODIFIED="1788293628728" TEXT="Inhaltlich geh&#xf6;rt es aber n&#xe4;her zum ParamData-Record"/>
 </node>
 </node>
-<node CREATED="1788279465992" ID="ID_511934631" MODIFIED="1788296935023" TEXT="Insgesamt entsteht hier eine Konkretisierungs-Kette">
+<node CREATED="1788279465992" ID="ID_511934631" MODIFIED="1788307762955" TEXT="Insgesamt entsteht hier eine Konkretisierungs-Kette">
+<linktarget COLOR="#4d65b9" DESTINATION="ID_511934631" ENDARROW="Default" ENDINCLINATION="-379;20;" ID="Arrow_ID_927557846" SOURCE="ID_1002785268" STARTARROW="None" STARTINCLINATION="119;14;"/>
 <icon BUILTIN="forward"/>
 <node CREATED="1788279482831" ID="ID_1252818882" MODIFIED="1788279536466" TEXT="wir gehen vom Kontrakt zum Service">
 <richcontent TYPE="NOTE"><html>
@ -84512,6 +84522,33 @@
 </node>
 <node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1788296987347" ID="ID_1409086602" MODIFIED="1788297005246" TEXT="kann nun die Implementierung konstruieren">
 <icon BUILTIN="pencil"/>
+<node CREATED="1788307857528" ID="ID_412964688" MODIFIED="1788307872683" TEXT="Value-Init &#x27f6; direkt vom Builder in den Konstruktor"/>
+<node CREATED="1788307874399" ID="ID_195138202" MODIFIED="1788307912949" TEXT="Get mit Typ-Konversion &#x27f6; generisches front-End auf dem Disposition-Interface">
+<node CREATED="1788307916543" ID="ID_877977052" MODIFIED="1788307932499" TEXT="so mu&#xdf; es sein &#x2014; daf&#xfc;r haben wir ein Interface"/>
+<node CREATED="1788307933286" ID="ID_67518693" MODIFIED="1788307948939" TEXT="die Implementierung baut dann auf den Basis-Interfaces auf"/>
+<node BACKGROUND_COLOR="#f8f1cb" COLOR="#a50125" CREATED="1788308332698" ID="ID_1468282295" MODIFIED="1788308358560" TEXT="Problem: brauche hier die BaseDomain-ID ohne Indirektion">
+<icon BUILTIN="messagebox_warning"/>
+<node BACKGROUND_COLOR="#fafe99" COLOR="#fa002a" CREATED="1788309764989" ID="ID_137382885" MODIFIED="1788309793594" TEXT="Alarm: das Design geht hier nicht auf">
+<icon BUILTIN="broken-line"/>
+<node CREATED="1788309801877" ID="ID_1982340657" MODIFIED="1788309820758" TEXT="auf der Interface-Ebene fehlen mir relevante Informationen"/>
+<node CREATED="1788309821442" ID="ID_1283728464" MODIFIED="1788309832720" TEXT="aber per Voraussetzung will ich keine Indirektion"/>
+<node CREATED="1788309836170" ID="ID_1386925847" MODIFIED="1788309890528" TEXT="und das Implementation-Layout sollte komplett frei konfigurierbar bleiben">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      auch im Hinblick darauf, da&#223; ich sp&#228;ter mal (m&#246;glichst mit dem gleichen generischen Code) auch komplexe Parameter-Typen handhaben m&#246;chte, wie Vektoren, Farb-Tripel und ganze Masken-Parameters&#228;tze...
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="messagebox_warning"/>
+</node>
+</node>
+</node>
+</node>
 </node>
 </node>
 </node>
@ -84590,10 +84627,11 @@
 </node>
 <node CREATED="1788203329439" ID="ID_1991597342" MODIFIED="1788203340179" TEXT="Parameter-Basisfunktionen">
 <node CREATED="1788203369397" ID="ID_1275080112" MODIFIED="1788203381813" TEXT="treibe den Struktur-Aufbau">
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1788203394319" ID="ID_1002785268" MODIFIED="1788203455329" TEXT="Disposition festlegen">
+<node COLOR="#435e98" CREATED="1788203394319" ID="ID_1002785268" MODIFIED="1788307769571" TEXT="Disposition festlegen">
+<arrowlink COLOR="#4d65b9" DESTINATION="ID_511934631" ENDARROW="Default" ENDINCLINATION="-379;20;" ID="Arrow_ID_927557846" STARTARROW="None" STARTINCLINATION="119;14;"/>
 <icon BUILTIN="full-1"/>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1788203400185" ID="ID_900611719" MODIFIED="1788203458783" TEXT="Builder-Notation schaffen">
+<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1788203400185" ID="ID_900611719" MODIFIED="1788307794257" TEXT="Builder-Notation schaffen">
 <icon BUILTIN="full-2"/>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1788203422590" ID="ID_1249325546" MODIFIED="1788203462519" TEXT="Valure-Konversionen einbinden">