Make functions be able to call themselves

tests/integration/Functions.cpp

@@ -84,5 +84,24 @@ TEST_CASE( "Define script function and return", "[integration]" ) {
     delete script;
 }
 
+TEST_CASE( "Functions can call themselves", "[integration]" ) {
+    Script* script = Script::Create(
+            "val = 0\n"
+            "function add() \n"
+            "if val < 5 then\n"
+            "val = val + 1\n"
+            "add()\n"
+            "end\n"
+            "end");
+    REQUIRE(!script->Diagnostics -> HasErrors());
+    script->Evaluate();
+    script->CallFunction("add", {});
+
+    auto variable = script->GetVariable("val");
+    REQUIRE(variable->GetType()->GetClass() == TypeClass::Number);
+    REQUIRE(variable->EvaluateInteger() == 5);
+
+    delete script;
+}
 
 #endif