diff --git a/src/lib/diff/tree-mutator.hpp b/src/lib/diff/tree-mutator.hpp
index 6f985c940..a6829c161 100644
--- a/src/lib/diff/tree-mutator.hpp
+++ b/src/lib/diff/tree-mutator.hpp
@@ -285,27 +285,10 @@ namespace diff{
   
   namespace { // Mutator-Builder decorator components...
     
-    using lib::meta::_Fun;
     using std::forward;
     using std::move;
     
     
-    template<typename FUN, typename SIG>
-    struct has_Sig
-      : std::is_same<SIG, typename _Fun<FUN>::Sig>
-      { };
-    
-    /** verify the installed functors or lambdas expose the expected signature */
-#define ASSERT_VALID_SIGNATURE(_FUN_, _SIG_) \
-        static_assert (has_Sig<_FUN_, _SIG_>::value, "Function " STRINGIFY(_FUN_) " unsuitable, expected signature: " STRINGIFY(_SIG_));
-    
-    
-    
-    
-    
-    
-    
-    
     /**
      * Builder-DSL to create and configure a concrete TreeMutator
      * @remarks all generated follow-up builders are chained and
diff --git a/src/lib/meta/function.hpp b/src/lib/meta/function.hpp
index 548269b66..4f5617601 100644
--- a/src/lib/meta/function.hpp
+++ b/src/lib/meta/function.hpp
@@ -178,6 +178,31 @@ namespace meta{
   
   
   
+  /**
+   * Meta-function to check that some _function like_ entity
+   * offers the expected signature
+   * @tparam SIG signature type (e.g. `float(int, bool)`)
+   * @tparam FUN anything _function like_ (class with function call operator
+   *             or std::function instance, or λ instance or language function
+   *             reference or function pointer
+   */
+  template<typename FUN, typename SIG>
+  struct has_Sig
+    : std::is_same<SIG, typename _Fun<FUN>::Sig>
+    { };
+  
+  /**
+   * Macro for a compile-time check to verify the given
+   * generic functors or lambdas expose some expected signature.
+   * @remark typically used when configuring a template with custom adapters.
+   */
+#define ASSERT_VALID_SIGNATURE(_FUN_, _SIG_) \
+        static_assert (lib::meta::has_Sig<_FUN_, _SIG_>::value, \
+                       "Function " STRINGIFY(_FUN_) " unsuitable, expected signature: " STRINGIFY(_SIG_));
+  
+  
+  
+  
   
   
   
diff --git a/src/lib/split-splice.hpp b/src/lib/split-splice.hpp
index 6ccc8700b..2c8dd8bc6 100644
--- a/src/lib/split-splice.hpp
+++ b/src/lib/split-splice.hpp
@@ -32,9 +32,8 @@
 #define LIB_SPLIT_SPLICE_H
 
 #include "lib/error.hpp"
-//#include "steam/mobject/builder/fixture-change-detector.hpp"  ///////////TODO
-#include "lib/time/timevalue.hpp"
 #include "lib/meta/function.hpp"
+#include "lib/time/timevalue.hpp"
 #include "lib/nocopy.hpp"
 
 #include <array>
@@ -45,19 +44,7 @@ namespace lib {
   namespace error = lumiera::error;
   
   
-  namespace splitsplice {// Implementation of Split-Splice algorithm
-    
-    using lib::meta::_Fun;
-    
-    template<typename FUN, typename SIG>
-    struct has_Sig
-      : std::is_same<SIG, typename _Fun<FUN>::Sig>
-      { };
-    
-    /** verify the installed functors or lambdas expose the expected signature */
-#define ASSERT_VALID_SIGNATURE(_FUN_, _SIG_) \
-        static_assert (has_Sig<_FUN_, _SIG_>::value, "Function " STRINGIFY(_FUN_) " unsuitable, expected signature: " STRINGIFY(_SIG_));
-    
+  namespace splitsplice {/// Implementation of [»SplitSplice« algorithm](\ref splite-splice.cpp)
     
     
     /**