added casting getter for gameFormula

src/storm/logic/Formula.cpp

@@ -333,6 +333,14 @@ namespace storm {
             return dynamic_cast<EventuallyFormula const&>(*this);
         }
 
+        GameFormula& Formula::asGameFormula() {
+            return dynamic_cast<GameFormula&>(*this);
+        }
+
+        GameFormula const& Formula::asGameFormula() const {
+            return dynamic_cast<GameFormula const&>(*this);
+        }
+
         GloballyFormula& Formula::asGloballyFormula() {
             return dynamic_cast<GloballyFormula&>(*this);
         }

src/storm/logic/Formula.h

@@ -155,6 +155,9 @@ namespace storm {
             EventuallyFormula& asReachabilityTimeFormula();
             EventuallyFormula const& asReachabilityTimeFormula() const;
 
+            GameFormula& asGameFormula();
+            GameFormula const& asGameFormula() const;
+
             GloballyFormula& asGloballyFormula();
             GloballyFormula const& asGloballyFormula() const;