From 68f6b9c9f4693df6ae761dd2651d06913b355152 Mon Sep 17 00:00:00 2001
From: simonpj <unknown>
Date: Thu, 24 Jul 2003 07:49:33 +0000
Subject: [PATCH] [project @ 2003-07-24 07:49:33 by simonpj] A gross hack to
 stop the pretty-printer going into an infinite loop. What
 happens is that 'indent' is given a negative number, and
 that made it loop.  This patch checks for the negative
 case, so at least it doesn't loop -- but I don't understand
 why the indent ever goes negative, so there's still
 something wrong here.

---
 Text/PrettyPrint/HughesPJ.hs |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Text/PrettyPrint/HughesPJ.hs b/Text/PrettyPrint/HughesPJ.hs
index 58f098b..6a95b4d 100644
--- a/Text/PrettyPrint/HughesPJ.hs
+++ b/Text/PrettyPrint/HughesPJ.hs
@@ -881,6 +881,15 @@ indent n | n >= 8 = '\t' : indent (n - 8)
 multi_ch 0 ch = ""
 multi_ch n       ch = ch : multi_ch (n - 1) ch
 
-spaces 0 = ""
-spaces n       = ' ' : spaces (n - 1)
+-- (spaces n) generates a list of n spaces
+--
+-- It should never be called with 'n' < 0, but that can happen for reasons I don't understand
+-- Here's a test case:
+--	ncat x y = nest 4 $ cat [ x, y ]
+--	d1 = foldl1 ncat $ take 50 $ repeat $ char 'a'
+--	d2 = parens $  sep [ d1, text "+" , d1 ]
+--	main = print d2
+-- I don't feel motivated enough to find the Real Bug, so meanwhile we just test for n<=0
+spaces n | n <= 0    = ""
+	 | otherwise = ' ' : spaces (n - 1)
 
-- 
1.7.10.4