From 069c6e80005874abbc8d4f82a96c782cb8dda111 Mon Sep 17 00:00:00 2001
From: Adam Chlipala <adam@chlipala.net>
Date: Sat, 3 May 2014 07:59:45 -0400
Subject: A .urs comment about [queryL*]

---
 lib/ur/top.urs | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'lib')

diff --git a/lib/ur/top.urs b/lib/ur/top.urs
index 30f1eaad..2ea86dc4 100644
--- a/lib/ur/top.urs
+++ b/lib/ur/top.urs
@@ -155,6 +155,10 @@ val mapX3 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type)
             -> r ::: {K} -> folder r
             -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> xml ctx [] []
 
+(* Note that the next two functions return elements in the _reverse_ of the natural order!
+ * Such a choice interacts well with the time complexity of standard list operations.
+ * It's easy to regain the natural order by inverting a query's 'ORDER BY' condition. *)
+
 val queryL : tables ::: {{Type}} -> exps ::: {Type}
              -> [tables ~ exps] =>
                   sql_query [] [] tables exps
-- 
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