From 2818b21129c9db9c853b1c4d972c0359c0ff8769 Mon Sep 17 00:00:00 2001
From: Yuri Tatishchev <itatishch@gmail.com>
Date: Sun, 8 Feb 2026 16:34:21 -0800
Subject: [PATCH] lab03: impl evalueate if

---
 lab03/interp.lhs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lab03/interp.lhs b/lab03/interp.lhs
index 2704bd3..6b0d2d1 100644
--- a/lab03/interp.lhs
+++ b/lab03/interp.lhs
@@ -85,7 +85,10 @@ You must complete the other cases.
 > evaluate :: Exp -> Val
 > evaluate ETrue = VTrue
 > evaluate EFalse = VFalse
-> evaluate (Eif e1 e2 e3) = error "TBD"
+> evaluate (Eif e1 e2 e3) =
+>   case evaluate e1 of
+>     VTrue  -> evaluate e2
+>     VFalse -> evaluate e3
 
 
 And here we have a couple of programs to test.