Implements string evaluation and concat

src/Evaluator/EvalValues/EvalValue.hpp

@@ -5,6 +5,7 @@
 #include "../../ScriptType.hpp"
 #include "../EvaluationException.hpp"
 #include <string>
+#include <sstream>
 
 class EvalValue{
 public:
@@ -57,6 +58,12 @@ public:
             return false;
         return this->EvaluateBool() == b->EvaluateBool();
     };
+
+    std::string EvaluateString() final{
+        std::ostringstream strs;
+        strs << _value;
+        return strs.str();
+    }
 };
 
 #endif //PORYGONLANG_EVALVALUE_HPP