Parse abstractions

Got tricked with or()'s function eagerness: Even when the left hand
side succeeds, the argument was evaluated which consumed a token in
the parser which prevented proper parsing.

1 files changed, 3 insertions, 1 deletions

diff --git a/rust/src/ast.rs b/rust/src/ast.rs
index 0493f59..722e9e0 100644
--- a/rust/src/ast.rs
+++ b/rust/src/ast.rs
@@ -1,11 +1,12 @@
 use std::fmt::{self, Display};
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub enum Value {
     Num(i32),
     Bool(bool),
     Sym(String),
     App(Box<Value>, Box<Value>),
+    Lam(String, Box<Value>),
 }
 
 impl Display for Value {
@@ -15,6 +16,7 @@ impl Display for Value {
             Value::Bool(b) => write!(f, "{}", b),
             Value::Sym(s) => write!(f, "{}", s),
             Value::App(l, r) => write!(f, "({} {})", l, r),
+            Value::Lam(var, body) => write!(f, "(lam {} {})", var, body),
         }
     }
 }