diff --git a/include/ground.h b/include/ground.h
index 98d1092..abbdd6d 100644
--- a/include/ground.h
+++ b/include/ground.h
@@ -300,6 +300,9 @@ struct GroundBytecodeFunction {
     GroundBytecodeHeap* closure;
 
     GroundSize _requiredSize;
+
+    // Only for native function 
+    GroundType* returnType;
 };
 struct GroundBytecodeStruct {};
 struct GroundBytecodeObject {};
diff --git a/src/Bytecode/Instruction/execute.c b/src/Bytecode/Instruction/execute.c
index 1166cd8..9c643be 100644
--- a/src/Bytecode/Instruction/execute.c
+++ b/src/Bytecode/Instruction/execute.c
@@ -82,14 +82,12 @@ struct GroundExecutionResult _GroundBytecodeInstructionExecute(GroundBytecodeIns
     PRINT: {
         for (GroundSize i = 0; i < instruction->args.len; i++) {
             printValue(HEAP_GET(heap, instruction->args.at[i]));
-            printf(" ");
         }
         return CONTINUE;
     }
     PRINTLN: {
         for (GroundSize i = 0; i < instruction->args.len; i++) {
             printValue(HEAP_GET(heap, instruction->args.at[i]));
-            printf(" ");
         }
         printf("\n");
         return CONTINUE;
@@ -835,21 +833,64 @@ struct GroundExecutionResult _GroundBytecodeInstructionExecute(GroundBytecodeIns
         GroundBytecodeFunction bf = {
             .isNativeFunction = true,
             .closure = NULL,
-            .program.native = handle,
+            .program.native = function,
             .args = {
                 .at = malloc(sizeof(GroundFunctionArg) * argsSize),
                 .capacity = argsSize,
                 .count = argsSize
             },
+            .returnType = malloc(sizeof(GroundType))
         };
-        if (bf.args.at == NULL) {
+        if (bf.args.at == NULL || bf.returnType == NULL) {
             Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
             Ground.Flags.error = true;
             return CONTINUE;
         }
-        for (size_t i = 0; i < argsSize; i++) {
 
+        enum GroundTypeType returnTypeType = HEAP_GET(heap, instruction->args.at[3])->type.type;
+
+        switch (returnTypeType) {
+            case GroundType_Struct: {
+                bf.returnType->type = GroundType_Object;
+                // TODO implement structs
+                break;
+            }
+            case GroundType_CoreType: {
+                bf.returnType->type = HEAP_GET(heap, instruction->args.at[3])->as.CoreType;
+                break;
+            }
+            default: {
+                // should have been caught elsewhere, not really our problem
+                break;
+            }
         }
+
+        for (size_t i = 0; i < argsSize; i++) {
+            enum GroundTypeType argTypeType = HEAP_GET(heap, instruction->args.at[i + 4])->as.CoreType;
+            switch (argTypeType) {
+                case GroundType_Struct: {
+                    bf.args.at[i].as.type.type = GroundType_Object;
+                    // TODO implement structs
+                    break;
+                }
+                case GroundType_CoreType: {
+                    bf.args.at[i].as.type.type = HEAP_GET(heap, instruction->args.at[3])->as.CoreType;
+                    break;
+                }
+                default: {
+                    // should have been caught elsewhere, not really our problem
+                    break;
+                }
+            }
+        }
+
+        GroundBytecodeValue val = {
+            .type = {GroundType_Function},
+            .as.Function = bf
+        };
+
+        HEAP_SET(heap, instruction->args.at[3], val);
+
         return CONTINUE;
     }
     CREATELABEL: {