diff --git a/ablescript/src/variables.rs b/ablescript/src/variables.rs
index 0a5fbb6..91c3c77 100644
--- a/ablescript/src/variables.rs
+++ b/ablescript/src/variables.rs
@@ -28,6 +28,7 @@ impl Abool {
         }
     }
 }
+
 impl Display for Abool {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -140,6 +141,7 @@ pub type Cart = HashMap<Value, ValueRef>;
 #[derive(Debug, Clone)]
 pub enum Value {
     Nul,
+    Undefined,
     Str(String),
     Int(isize),
     Abool(Abool),
@@ -157,7 +159,7 @@ impl Hash for Value {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         discriminant(self).hash(state);
         match self {
-            Value::Nul => (),
+            Value::Nul | Value::Undefined => (),
             Value::Str(v) => v.hash(state),
             Value::Int(v) => v.hash(state),
             Value::Abool(v) => v.to_string().hash(state),
@@ -211,6 +213,7 @@ impl Value {
             },
             Value::Int(i) => i,
             Value::Nul => consts::ANSWER,
+            Value::Undefined => todo!("undefined -> isize coercion"),
             Value::Str(text) => text
                 .parse()
                 .unwrap_or_else(|_| text.chars().map(|cr| cr as isize).sum()),
@@ -225,6 +228,7 @@ impl Value {
     pub fn into_abool(self) -> Abool {
         match self {
             Value::Nul => Abool::Never,
+            Value::Undefined => Abool::Sometimes,
             Value::Str(s) => match s.to_lowercase().as_str() {
                 "never" | "no" | "🇳🇴" => Abool::Never,
                 "sometimes" => Abool::Sometimes,
@@ -292,6 +296,7 @@ impl Value {
                 body: vec![],
                 params: vec![],
             },
+            Value::Undefined => todo!("undefined -> functio coercion"),
             Value::Str(s) => Functio::Eval(s),
             Value::Int(i) => Functio::Bf {
                 instructions: {
@@ -345,6 +350,7 @@ impl Value {
     pub fn into_cart(self) -> Cart {
         match self {
             Value::Nul => HashMap::new(),
+            Value::Undefined => todo!("undefined -> cart coercion"),
             Value::Str(s) => s
                 .chars()
                 .enumerate()
@@ -452,6 +458,7 @@ impl Value {
     pub fn length(&self) -> isize {
         match self {
             Value::Nul => 0,
+            Value::Undefined => todo!("undefined length"),
             Value::Str(s) => s.len() as _,
             Value::Int(i) => i.count_zeros() as _,
             Value::Abool(a) => match a {
@@ -502,8 +509,9 @@ impl ops::Add for Value {
 
     fn add(self, rhs: Self) -> Self::Output {
         match self {
-            Value::Nul => match rhs {
+            Value::Nul | Value::Undefined => match rhs {
                 Value::Nul => Value::Nul,
+                Value::Undefined => Value::Undefined,
                 Value::Str(_) => Value::Str(self.to_string()) + rhs,
                 Value::Int(_) => Value::Int(self.into_isize()) + rhs,
                 Value::Abool(_) => Value::Abool(self.into_abool()) + rhs,
@@ -531,8 +539,9 @@ impl ops::Sub for Value {
 
     fn sub(self, rhs: Self) -> Self::Output {
         match self {
-            Value::Nul => match rhs {
+            Value::Nul | Value::Undefined => match rhs {
                 Value::Nul => Value::Nul,
+                Value::Undefined => Value::Undefined,
                 Value::Str(_) => Value::Str(self.to_string()) - rhs,
                 Value::Int(_) => Value::Int(self.into_isize()) - rhs,
                 Value::Abool(_) => Value::Abool(self.into_abool()) - rhs,
@@ -648,8 +657,9 @@ impl ops::Mul for Value {
 
     fn mul(self, rhs: Self) -> Self::Output {
         match self {
-            Value::Nul => match rhs {
+            Value::Nul | Value::Undefined => match rhs {
                 Value::Nul => Value::Nul,
+                Value::Undefined => Value::Undefined,
                 Value::Str(_) => Value::Str(self.to_string()) * rhs,
                 Value::Int(_) => Value::Int(self.into_isize()) * rhs,
                 Value::Abool(_) => Value::Abool(self.into_abool()) * rhs,
@@ -689,8 +699,9 @@ impl ops::Div for Value {
 
     fn div(self, rhs: Self) -> Self::Output {
         match self {
-            Value::Nul => match rhs {
+            Value::Nul | Value::Undefined => match rhs {
                 Value::Nul => Value::Nul,
+                Value::Undefined => Value::Undefined,
                 Value::Str(_) => Value::Str(self.to_string()) / rhs,
                 Value::Int(_) => Value::Int(self.into_isize()) / rhs,
                 Value::Abool(_) => Value::Abool(self.into_abool()) / rhs,
@@ -793,7 +804,8 @@ impl ops::Not for Value {
 
     fn not(self) -> Self::Output {
         match self {
-            Value::Nul => Value::Nul,
+            Value::Nul => Value::Undefined,
+            Value::Undefined => Value::Nul,
             Value::Str(s) => Value::Str(s.chars().rev().collect()),
             Value::Int(i) => Value::Int(i.swap_bytes()),
             Value::Abool(a) => Value::Abool(match a {
@@ -856,6 +868,7 @@ impl PartialEq for Value {
 
         match self {
             Value::Nul => matches!(other, Value::Nul),
+            Value::Undefined => matches!(other, Value::Undefined),
             Value::Str(s) => *s == other.to_string(),
             Value::Int(i) => *i == other.into_isize(),
             Value::Abool(a) => *a == other.into_abool(),
@@ -873,18 +886,14 @@ impl PartialOrd for Value {
         let other = other.clone();
 
         match self {
-            Value::Nul => {
-                if other == Value::Nul {
-                    Some(Equal)
-                } else {
-                    None
-                }
-            }
+            Value::Nul if other == Value::Nul => Some(Equal),
+            Value::Undefined if other == Value::Undefined => Some(Equal),
             Value::Str(s) => Some(s.cmp(&other.to_string())),
             Value::Int(i) => Some(i.cmp(&other.into_isize())),
             Value::Abool(a) => a.partial_cmp(&other.into_abool()),
             Value::Functio(_) => self.clone().into_isize().partial_cmp(&other.into_isize()),
             Value::Cart(c) => Some(c.len().cmp(&other.into_cart().len())),
+            Value::Nul | Value::Undefined => None,
         }
     }
 }
@@ -893,6 +902,7 @@ impl Display for Value {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             Value::Nul => write!(f, "nul"),
+            Value::Undefined => write!(f, "undefined"),
             Value::Str(v) => write!(f, "{}", v),
             Value::Int(v) => write!(f, "{}", v),
             Value::Abool(v) => write!(f, "{}", v),