diff --git a/ablescript/src/variables.rs b/ablescript/src/variables.rs
index 60487dfe..805c54ef 100644
--- a/ablescript/src/variables.rs
+++ b/ablescript/src/variables.rs
@@ -184,7 +184,7 @@ impl Value {
                         .sum::<i32>()
                         + body.len() as i32
                 }
-                Functio::Builtin(b) => b.fn_addr() as _,
+                Functio::Builtin(b) => (b.fn_addr() + b.arity) as _,
                 Functio::Chain { functios, kind } => {
                     let (lf, rf) = *functios;
                     Value::Functio(lf).into_i32()