WIP: draft some basic properties of a GenNode

- can build from the supported value types
- is optionally named
- is copyable value, but only assignable within one payload type
- is recursive, for object / tree representation

tests/library/diff/gen-node-basic-test.cpp

@@ -25,14 +25,18 @@
 #include "lib/test/test-helper.hpp"
 #include "lib/diff/gen-node.hpp"
 #include "lib/diff/record.hpp"
+#include "lib/util.hpp"
 
 //#include <utility>
 //#include <string>
 //#include <vector>
+#include <cmath>
 
+using util::contains;
 //using std::string;
 //using std::vector;
 //using std::swap;
+using std::fabs;
 
 
 namespace lib {
@@ -40,6 +44,7 @@ namespace diff{
 namespace test{
   
 //  using lumiera::error::LUMIERA_ERROR_LOGIC;
+  using error::LUMIERA_ERROR_WRONG_TYPE;
   
   namespace {//Test fixture....
     
@@ -79,6 +84,43 @@ namespace test{
       void
       simpleUsage()
         {
+          // can build from the supported value types
+          GenNode n1(42);
+          CHECK (42 == n1.data.get<int>());
+          CHECK (!n1.isNamed());
+          CHECK (contains (n1.idi.getSym(), "_CHILD_"));
+          
+          // can optionally be named
+          GenNode n2("π", 3.14159265358979323846264338328);
+          CHECK (fabs (3.14159265 - n2.data.get<double>) < 1e-5 );
+          CHECK (n2.isNamed());
+          CHECK ("π" == n2.idi.getSym());
+          
+          // is a copyable value
+          GenNode n11(n1);
+          CHECK (n1 == n11);
+          CHECK (42 == n11.data.get<int>());
+          
+          // is assignable with compatible payload value
+          n11.data = 24;
+          CHECK (n1 != n11);
+          CHECK (24 == n11.data.get<int>());
+          CHECK (42 == n1.data.get<int>());
+          
+          // is assignable within the same kind of value
+          n1 = n11;
+          CHECK (n1 == n11);
+          
+          // but assignment may not alter payload type
+          VERIFY_ERROR (WRONG_TYPE, n1 = n2 );
+          
+          // can build recursive data structures
+          GenNode n3(Rec({"spam", GenNode("ham", "eggs")}));
+          CHECK ("spam" == n3.data.get<Rec>().getType());
+          CHECK ("eggs" == n3.data.get<Rec>().get("ham").data.get<string>());
+          CHECK ("ham"  == n3.data.get<Rec>().get("ham").idi.getSym());
+          CHECK (n3.data.get<Rec>().get("ham").isNamed());
+          CHECK (!n3.isNamed());
         }