From b7e3c861031ee40b4e62a48a92b2666706c7c4d3 Mon Sep 17 00:00:00 2001
From: Jim Pryor <profjim@jimpryor.net>
Date: Sun, 3 Oct 2010 10:34:36 -0400
Subject: [PATCH] add list_equal to library (commented out)

Signed-off-by: Jim Pryor <profjim@jimpryor.net>
---
 lambda_library.mdwn | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/lambda_library.mdwn b/lambda_library.mdwn
index f0b4f441..ff363756 100644
--- a/lambda_library.mdwn
+++ b/lambda_library.mdwn
@@ -296,3 +296,28 @@ and all sorts of other places. Others of them are our own handiwork.
 
 
 -->
+
+<!--
+let list_equal =
+    \left right. left
+                ; here's our f
+                (\hd sofar.
+                    ; deconstruct our sofar-pair
+                    sofar (\might_be_equal right_tail.
+                        ; our new sofar
+                        make_pair
+                        (and (and might_be_equal (not (isempty right_tail))) (eq? hd (head right_tail)))
+                        (tail right_tail)
+                    ))
+                ; here's our z
+                ; we pass along the fold a pair
+                ; (might_for_all_i_know_still_be_equal?, tail_of_reversed_right)
+                ; when left is empty, the lists are equal if right is empty
+                (make_pair
+                    (not (isempty right))
+                    (reverse right)
+                )
+                ; when fold is finished, check sofar-pair
+                (\might_be_equal right_tail. and might_be_equal (isempty right_tail))
+-->
+
-- 
2.11.0