Implements variable usage, tweaks and fixes for variable assignment

src/Evaluator/EvalValues/EvalValue.hpp

@@ -9,6 +9,7 @@
 
 class EvalValue{
 public:
+    EvalValue() = default;
     virtual ~EvalValue() = default;
     virtual ScriptType* GetType() = 0;
 
@@ -18,6 +19,8 @@ public:
         return ! (this->operator==(b));
     }
 
+    virtual EvalValue* Clone() = 0;
+
     virtual long EvaluateInteger(){
         throw EvaluationException("Can't evaluate this EvalValue as integer.");
     }
@@ -41,6 +44,10 @@ public:
         _type = new ScriptType(TypeClass::Bool);
     }
 
+    EvalValue* Clone() final{
+        return new BooleanEvalValue(_value);
+    }
+
     ~BooleanEvalValue() final{
         delete _type;
     }