diff --git a/src/main.rs b/src/main.rs
index fdb9362..ea39b7c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,6 +7,28 @@ use crate::parse::ast::*;
 pub mod parse;
 
 fn main() {
-    let fc = fasm_codegen(&vec![Expr::VarDefinition(VarDefinition {name: "goren", value: Value::Number(10)}), Expr::MathExpr(Math { left: Value::Var(VarReference { name: "goren"}), right: Value::Number(17), operator: MathOperator::OP_MULT}), Expr::FunDefinition(FunDefinition {name: "adder", contents: vec![Expr::MathExpr(Math {left: Value::Param(ParamReference {param_number: 0}), right: Value::Param(ParamReference {param_number: 1}), operator: MathOperator::OP_ADD})]}), Expr::Breakpoint], true);
+    let fc = fasm_codegen(&
+                          vec![
+                              Expr::VarDefinition(VarDefinition {name: "goren", value: Value::Number(10)}),
+                              Expr::MathExpr(Math {
+                                  left: &Value::Var(VarReference { name: "goren"}),
+                                  right: &Value::Number(17),
+                                  operator: MathOperator::OP_MULT
+                              }
+                              ),
+                              Expr::FunDefinition(FunDefinition {
+                                  name: "adder", contents: vec![
+                                      Expr::Return(Value::Math(
+                                          Math {
+                                              left: &Value::Param(ParamReference {param_number: 0}),
+                                              right: &Value::Param(ParamReference {param_number: 1}),
+                                              operator: MathOperator::OP_ADD
+                                          }
+                                      ))
+                                  ]
+                              }),
+                              Expr::Breakpoint],
+                          true
+    );
     println!("{}", fc);
 }
diff --git a/src/parse/ast.rs b/src/parse/ast.rs
index bf20a51..5bf5acb 100644
--- a/src/parse/ast.rs
+++ b/src/parse/ast.rs
@@ -10,14 +10,14 @@ pub enum Expr<'a> {
 
 // MATH EXPRESSION
 
-#[derive(Debug)]
+#[derive(Debug, Copy, Clone)]
 pub struct Math<'a> {
-    pub left: Value<'a>,
-    pub right: Value<'a>,
+    pub left: &'a Value<'a>,
+    pub right: &'a Value<'a>,
     pub operator: MathOperator
 }
 
-#[derive(Debug)]
+#[derive(Debug, Copy, Clone)]
 pub enum MathOperator {
     OP_ADD,	// Addition
     OP_SUB,	// Subtraction
@@ -59,6 +59,7 @@ pub struct VarDefinition<'a> {
     pub value: Value<'a>,
 }
 
+
 #[derive(Debug, Copy, Clone)]
 pub struct VarReference<'a> {
     pub name: &'a str,
@@ -74,7 +75,7 @@ pub enum Value<'a> {
     Var(VarReference<'a>),
     Param(ParamReference),
     Number(u64),
-    Math(Math),
+    Math(Math<'a>),
 }
 
 impl<'a> Value<'a> {