diff --git a/ablescript/src/interpret.rs b/ablescript/src/interpret.rs
index 044e9e3..bb79d33 100644
--- a/ablescript/src/interpret.rs
+++ b/ablescript/src/interpret.rs
@@ -175,7 +175,7 @@ impl ExecEnv {
                     .map(|x| x.borrow().clone())
                     .unwrap_or(Value::Nul)
             }
-            Len(_) => todo!("length"),
+            Len(expr) => Value::Int(self.eval_expr(expr)?.len()),
 
             // TODO: not too happy with constructing an artificial
             // Ident here.
diff --git a/ablescript/src/variables.rs b/ablescript/src/variables.rs
index 5d42a19..9b85c18 100644
--- a/ablescript/src/variables.rs
+++ b/ablescript/src/variables.rs
@@ -122,36 +122,10 @@ impl Value {
         match self {
             Value::Abool(a) => a as _,
             Value::Bool(b) => b as _,
-            Value::Functio(func) => match func {
-                // Compares lengths of functions:
-                // BfFunctio - Sum of lengths of instructions and length of tape
-                // AbleFunctio - Sum of argument count and body length
-                // Eval - Length of input code
-                Functio::Bf {
-                    instructions,
-                    tape_len,
-                } => (instructions.len() + tape_len) as _,
-                Functio::Able { params, body } => (params.len() + format!("{:?}", body).len()) as _,
-                Functio::Chain { functios, kind } => {
-                    let (lhs, rhs) = *functios;
-                    match kind {
-                        FunctioChainKind::Equal => {
-                            Value::Int(Value::Functio(lhs).into_i32())
-                                + Value::Int(Value::Functio(rhs).into_i32())
-                        }
-                        FunctioChainKind::ByArity => {
-                            Value::Int(Value::Functio(lhs).into_i32())
-                                * Value::Int(Value::Functio(rhs).into_i32())
-                        }
-                    }
-                    .into_i32()
-                }
-                Functio::Eval(s) => s.len() as _,
-            },
             Value::Int(i) => i,
             Value::Nul => consts::ANSWER,
             Value::Str(text) => text.parse().unwrap_or(consts::ANSWER),
-            Value::Cart(c) => c.len() as _,
+            _ => self.len() as _,
         }
     }
 
@@ -410,6 +384,55 @@ impl Value {
             Value::Cart(c) => c,
         }
     }
+
+    /// Get a lenght of a value
+    pub fn len(&self) -> i32 {
+        match self {
+            Value::Nul => 0,
+            Value::Str(s) => s.len() as _,
+            Value::Int(i) => i.count_zeros() as _,
+            Value::Bool(b) if *b => -2,
+            Value::Bool(_) => 2,
+            Value::Abool(a) => match a {
+                Abool::Never => -3,
+                Abool::Sometimes => {
+                    if rand::thread_rng().gen() {
+                        3
+                    } else {
+                        -3
+                    }
+                }
+                Abool::Always => 3,
+            },
+            Value::Functio(f) => match f {
+                // Compares lengths of functions:
+                // BfFunctio - Sum of lengths of instructions and length of tape
+                // AbleFunctio - Sum of argument count and body length
+                // Eval - Length of input code
+                Functio::Bf {
+                    instructions,
+                    tape_len,
+                } => (instructions.len() + tape_len) as _,
+                Functio::Able { params, body } => (params.len() + format!("{:?}", body).len()) as _,
+                Functio::Chain { functios, kind } => {
+                    let (lhs, rhs) = *functios.clone();
+                    match kind {
+                        FunctioChainKind::Equal => {
+                            Value::Int(Value::Functio(lhs).into_i32())
+                                + Value::Int(Value::Functio(rhs).into_i32())
+                        }
+                        FunctioChainKind::ByArity => {
+                            Value::Int(Value::Functio(lhs).into_i32())
+                                * Value::Int(Value::Functio(rhs).into_i32())
+                        }
+                    }
+                    .into_i32()
+                }
+                Functio::Eval(s) => s.len() as _,
+            },
+            Value::Cart(c) => c.len() as _,
+        }
+    }
 }
 
 impl ops::Add for Value {