better use a named magic constant

right now, what we actually need here is just some integer,
so the GenNode payload is typed to int (or just to anything
different than a Record, because the Record signals that
we intend to bind, not to invoke the command)

src/gui/interact/invocation-trail.hpp

@@ -52,11 +52,6 @@
 #include <string>
 
 
-/** @todo unused as of 11/2015
- * some additional instantiation metadata
- * could be passed alongside with the invocation.
- */
-#define RESERVED_FOR_FUTURE_USE_ 42
 
 
 namespace gui {
@@ -103,9 +98,17 @@ namespace interact {
       
       GenNode bang()  const
         {
-          return GenNode(cmdID_, RESERVED_FOR_FUTURE_USE_);
+          return GenNode(cmdID_, int(DO_IT));
         }
       
+      
+      /** @todo unused as of 11/2015
+       * some additional instantiation metadata
+       * could be passed alongside with the invocation. */
+      enum { DO_IT = 42 };
+      
+      
+      
       string
       getID()  const
         {

tests/gui/abstract-tangible-test.cpp

@@ -344,7 +344,7 @@ namespace test {
           
           CHECK (dummyState == concreteParam);  // command was indeed invoked
           CHECK (nexusLog.verifyCall("act").arg("«int»|" +toString(concreteParam))
-                         .beforeCall("act").arg("DataCap|«int»|"));
+                         .beforeCall("act").arg("DataCap|«int»|" +toString(int(InvocationTrail::DO_IT))));
           CHECK (nexusLog.verifyEvent("binding for command \""+DUMMY_CMD_ID)
                          .beforeEvent("invoke command \""+DUMMY_CMD_ID));