Introduce let-expressions

1 files changed, 2 insertions, 0 deletions

diff --git a/rust/src/ast.rs b/rust/src/ast.rs
index 8729fa2..2221856 100644
--- a/rust/src/ast.rs
+++ b/rust/src/ast.rs
@@ -8,6 +8,7 @@ pub enum Value {
     App(Box<Value>, Box<Value>),
     Lam(String, Box<Value>),
     Def(String, Box<Value>),
+    Let(String, Box<Value>, Box<Value>),
 }
 
 impl Display for Value {
@@ -19,6 +20,7 @@ impl Display for Value {
             Value::App(l, r) => write!(f, "({} {})", l, r),
             Value::Lam(var, body) => write!(f, "(lam {} {})", var, body),
             Value::Def(var, value) => write!(f, "(def {} {})", var, value),
+            Value::Let(var, value, body) => write!(f, "(let ({} {}) {})", var, value, body),
         }
     }
 }