diff --git a/src/interpreter/value.rs b/src/interpreter/value.rs
index 82da70b..bc425e2 100644
--- a/src/interpreter/value.rs
+++ b/src/interpreter/value.rs
@@ -1,21 +1,36 @@
+use std::{cell::RefCell, rc::Rc};
+
+use super::Callable;
+
 /// A value being handled by the interpreter.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone)]
 pub enum Value {
     Nil,
     Boolean(bool),
     String(String),
     Number(f64),
+    Callable(Rc<RefCell<dyn Callable>>),
+}
+
+impl PartialEq for Value {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (Self::Nil, Self::Nil) => true,
+            (Self::Boolean(a), Self::Boolean(b)) => a == b,
+            (Self::String(a), Self::String(b)) => a == b,
+            (Self::Number(a), Self::Number(b)) => a == b,
+            _ => false,
+        }
+    }
 }
 
 impl Value {
     /// Check whether a value is truthy or not.
     pub fn is_truthy(&self) -> bool {
-        if self == &Value::Nil {
-            false
-        } else if let Value::Boolean(b) = self {
-            *b
-        } else {
-            true
+        match self {
+            &Self::Nil => false,
+            &Self::Boolean(b) => b,
+            _ => true,
         }
     }
 }