DOM

- Standardized DOM interface to return success/failure, with the possibility
  of blank values. This matches the Eval::source callback interface‥
- Added more unit tests.

src/commands/CmdCalc.cpp

@@ -25,6 +25,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include <Context.h>
+#include <Filter.h>
 #include <Eval.h>
 #include <Dates.h>
 #include <main.h>
@@ -33,20 +34,6 @@
 
 extern Context context;
 
-////////////////////////////////////////////////////////////////////////////////
-static bool domSource (const std::string& name, Variant& value)
-{
-  Task t;
-  std::string resolved = context.dom.get (name, t);
-  if (resolved != name)
-  {
-    value = Variant (resolved);
-    return true;
-  }
-
-  return false;
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 CmdCalc::CmdCalc ()
 {