diff --git a/src/run.rs b/src/run.rs
index 9403afb..550bac5 100644
--- a/src/run.rs
+++ b/src/run.rs
@@ -32,8 +32,8 @@ impl Debug for Function {
 
 #[derive(Debug, Clone, Default)]
 pub struct Scope {
-	pub variables: HashMap<String, ValueInner>,
-	pub functions: HashMap<String, Function>,
+	variables: HashMap<String, ValueInner>,
+	functions: HashMap<String, Function>,
 }
 
 impl Scope {
@@ -48,6 +48,11 @@ impl Scope {
 			self.variables.remove(&name);
 		}
 	}
+
+	pub fn add_fn(&mut self, name: &'static str, f: impl Fn(Vec<Value>) -> Value + 'static) {
+		self.functions
+			.insert(name.into(), Function::new(name.into(), f));
+	}
 }
 
 pub trait Eval {