From bc57ed9df00261a6aead99291543cc610259f54e Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Wed, 27 Sep 2023 22:38:32 -0600
Subject: [PATCH] Allow variable defs to use earlier names in list

---
 Interpreter.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Interpreter.cs b/Interpreter.cs
index 0c82e0a..af71bbc 100644
--- a/Interpreter.cs
+++ b/Interpreter.cs
@@ -490,7 +490,9 @@ public class Interpreter : AST.IExprVisitor<Env, object>
 			switch (binding)
 			{
 				case VarBinding(var pattern, var valueExpr):
-					var value = evaluate(env, valueExpr);
+					// By passing newEnv, we let the var definition refer to
+					// earlier bindings in the list.
+					var value = evaluate(newEnv, valueExpr);
 					try
 					{
 						pattern.accept((value, newEnv), new PatternBinder());