From 6555de359a612f725356b16be4ea8cfc7c0ca430 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@uber.com>
Date: Thu, 11 Mar 2021 09:28:06 +0200
Subject: [PATCH] add excuses

---
 IV/wm.sql | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/IV/wm.sql b/IV/wm.sql
index ab16593..f246702 100644
--- a/IV/wm.sql
+++ b/IV/wm.sql
@@ -228,6 +228,10 @@ begin
       continue when st_numgeometries(multi) = 2 and
         (st_contains(bends[j], a) or st_contains(bends[j], b));
 
+      -- Sincere apologies to someone who will need to debug the block below.
+      -- To understand it, I suggest you take a pencil and paper, draw a
+      -- self-crossing bend (fig6 from the article works well), and figure out
+      -- what happens here, by hand.
       prev_length = array_length(bends, 1);
       if j < i then
         -- remove first vertex of the following bend, because the last
@@ -251,7 +255,6 @@ begin
         bends = bends[1:i] || bends[j+1:prev_length];
       end if;
       j = j - prev_length + array_length(bends, 1);
-
     end loop;
 
   end loop;