diff --git a/include/ast/expression/FunctionDeclarationExpression.hpp b/include/ast/expression/FunctionDeclarationExpression.hpp
index 5c486f8..7ea41d1 100644
--- a/include/ast/expression/FunctionDeclarationExpression.hpp
+++ b/include/ast/expression/FunctionDeclarationExpression.hpp
@@ -21,6 +21,7 @@
 
 #include <ast/ASTNode.hpp>
 #include <ast/TerminativeSignal.hpp>
+#include <parser/Token.hpp>
 
 #include <memory>
 #include <string>
@@ -28,13 +29,13 @@
 
 class FunctionDeclarationExpression : public ASTNode {
 private:
-    std::vector<std::string> parameters;
+    std::vector<std::unique_ptr<Token>> parameters;
     std::unique_ptr<ASTNode> body;
 
 public:
     explicit FunctionDeclarationExpression(
         std::unique_ptr<Token> _address,
-        std::vector<std::string> _parameters,
+        std::vector<std::unique_ptr<Token>> _parameters,
         std::unique_ptr<ASTNode> _body
     ) : parameters(std::move(_parameters)),
         body(std::move(_body)) {
diff --git a/src/ast/expression/FunctionDeclarationExpression.cpp b/src/ast/expression/FunctionDeclarationExpression.cpp
index 18405fd..6a90553 100644
--- a/src/ast/expression/FunctionDeclarationExpression.cpp
+++ b/src/ast/expression/FunctionDeclarationExpression.cpp
@@ -44,7 +44,7 @@ DynamicObject FunctionDeclarationExpression::call(SymbolTable& symbols, const st
     SymbolTable localSymbols(&symbols);
     for(size_t i = 0; i < args.size(); ++i) {
         auto obj = std::move(&std::move(args).at(i));
-        localSymbols.setSymbol(this->parameters[i], obj);
+        localSymbols.setSymbol(this->parameters[i]->getImage(), obj);
     }
 
     return std::move(this->body->visit(localSymbols));