diff --git a/src/lib/iter-tree-explorer.hpp b/src/lib/iter-tree-explorer.hpp
index 7270a1683..2bf94e392 100644
--- a/src/lib/iter-tree-explorer.hpp
+++ b/src/lib/iter-tree-explorer.hpp
@@ -475,7 +475,7 @@ namespace lib {
      *             passing the type `SRC&` as argument. This instantiation may fail (and abort compilation),
      *             but when it succeeds, we can infer the result type `Res` from the generic lambda
      */
-    template<class SIG, typename SRC =void>
+    template<class FUN, typename SRC =void>
     struct _FunTraits
       {
         /** handle all regular "function-like" entities */
@@ -495,7 +495,7 @@ namespace lib {
           };
         
         
-        using Sig = typename FunDetector<SIG>::Sig;
+        using Sig = typename FunDetector<FUN>::Sig;
         using Arg = typename _Fun<Sig>::Args::List::Head;  // assuming function with a single argument
         using Res = typename _Fun<Sig>::Ret;
         
@@ -510,6 +510,8 @@ namespace lib {
                            "the bound functor must accept the source iterator or state core as parameter");
             
             static auto build() { return [](ARG& arg) -> ARG& { return arg; }; }
+            
+            static auto wrap (FUN&& rawFunctor) { return forward<FUN> (rawFunctor); }
           };
         
         /** adapt to a functor, which accepts the value type of the source sequence ("monadic" usage pattern) */
@@ -518,6 +520,8 @@ namespace lib {
                                                  ,__not_<is_convertible<IT, Arg>>>>>        // need to exclude the latter, since IterableDecorator
           {                                                                                //  often seems to accept IT::value_type (while in fact it doesn't)
             static auto build() { return [](auto& iter) { return *iter; }; }
+            
+            static auto wrap (function<Sig> rawFun) { return [rawFun](IT& srcIter) { return rawFun(*srcIter); }; }
           };
         
         /** adapt to a functor collaborating with an IterSource based iterator pipeline */
@@ -529,6 +533,8 @@ namespace lib {
             using Source = typename IT::Source;
             
             static auto build() { return [](auto& iter) -> Source& { return iter.source(); }; }
+            
+            static auto wrap (function<Sig> rawFun) { return [rawFun](IT& iter) { return rawFun(*iter.source()); }; }
           };
         
         
@@ -546,6 +552,13 @@ namespace lib {
                 return boundFunction (accessArg (arg));
               }
           };
+        
+        template<typename IT>
+        static auto
+        adaptFunctor (FUN&& rawFunctor)
+          {
+            return function<Res(IT&)> {ArgAdapter<IT>::wrap (forward<FUN> (rawFunctor))};
+          }
       };
     
     
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index d66335796..a892bba72 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -31269,7 +31269,7 @@
 </node>
 </node>
 </node>
-<node CREATED="1536441211468" ID="ID_435661366" MODIFIED="1536441216296" TEXT="L&#xf6;sungs-Idee">
+<node CREATED="1536441211468" HGAP="84" ID="ID_435661366" MODIFIED="1536451220949" TEXT="L&#xf6;sungs-Idee" VSHIFT="15">
 <node CREATED="1536441217427" ID="ID_1508660342" MODIFIED="1536441270931" TEXT="die Signatur im Builder konstruieren. Traits nur noch auf Signatur abst&#xfc;tzen">
 <icon BUILTIN="full-1"/>
 </node>
@@ -31308,6 +31308,57 @@
 <node CREATED="1536441367354" ID="ID_1778093460" MODIFIED="1536441424596" TEXT="welcher eine gegebene Funktion in eine vorgegebene function&lt;SIG&gt; einpasst"/>
 </node>
 </node>
+<node CREATED="1536451222025" HGAP="9" ID="ID_389572303" MODIFIED="1536451229468" TEXT="Umbau" VSHIFT="5">
+<node COLOR="#338800" CREATED="1536451240308" ID="ID_241157222" MODIFIED="1536451273762" TEXT="den SRC-Parameter optional machen">
+<icon BUILTIN="button_ok"/>
+</node>
+<node COLOR="#338800" CREATED="1536451256034" ID="ID_645889218" MODIFIED="1536451285944" TEXT="FunTraits sind idempotent">
+<icon BUILTIN="button_ok"/>
+<icon BUILTIN="ksmiletris"/>
+<node CREATED="1536451303308" ID="ID_1343290323" MODIFIED="1536451313142" TEXT="man kann sie mit dem Funktor aufrufen -&gt; Sig"/>
+<node CREATED="1536451313778" ID="ID_439029617" MODIFIED="1536451336475" TEXT="man kann sie mit Sig aufrufen -&gt; Arg, Ret"/>
+</node>
+<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1536451345998" ID="ID_1853688774" MODIFIED="1536451360667" TEXT="Funktor-Konstruktor-Funktion">
+<icon BUILTIN="pencil"/>
+<node CREATED="1536451365731" ID="ID_552359289" MODIFIED="1536451394878" TEXT="f&#xfc;r Aufruf aus dem Konstruktor-Kontext">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ...wo der volle Typ des Funktors FUN bekannt ist
+    </p>
+  </body>
+</html>
+</richcontent>
+</node>
+<node CREATED="1536451415725" ID="ID_1712691133" MODIFIED="1536451426247" TEXT="Bekommt SRC-Iterator als Template-Param"/>
+<node CREATED="1536451430508" ID="ID_224998497" MODIFIED="1536451471881" TEXT="wirft eine std::function&lt;Ret(SRC&amp;)&gt; ab"/>
+<node CREATED="1536451473013" ID="ID_1179844665" MODIFIED="1536451543886" TEXT="in die der eigentliche Funktor geeignet adaptiert ist">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ...und in dem besonders wichtigen Fall,
+    </p>
+    <p>
+      in dem der Funktor direkt den SRC-Iterator akzeptiert,
+    </p>
+    <p>
+      wird er ohne Weiteres durchgereicht.
+    </p>
+    <p>
+      In dem Fall dann <b>keine</b>&#160;doppelte Verpackung mehr!
+    </p>
+  </body>
+</html>
+</richcontent>
+</node>
+</node>
+</node>
 </node>
 </node>
 </node>