diff --git a/hledger-lib/Hledger/Data/Dates.hs b/hledger-lib/Hledger/Data/Dates.hs
index 5c8d46076..9c16862b1 100644
--- a/hledger-lib/Hledger/Data/Dates.hs
+++ b/hledger-lib/Hledger/Data/Dates.hs
@@ -77,6 +77,11 @@ import Text.Printf
 import Hledger.Data.Types
 import Hledger.Utils
 
+
+-- Help ppShow parse and line-wrap DateSpans better in debug output.
+instance Show DateSpan where
+    show (DateSpan s1 s2) = "DateSpan \"" ++ show s1 ++ "\" \"" ++ show s2 ++ "\""
+
 showDate :: Day -> String
 showDate = formatTime defaultTimeLocale "%0C%y/%m/%d"
 
@@ -672,11 +677,11 @@ tests_Hledger_Data_Dates = TestList
   ,"period expressions" ~: do
     let todaysdate = parsedate "2008/11/26"
     let str `gives` result = show (parsewith (periodexpr todaysdate) str) `is` ("Right " ++ result)
-    "from aug to oct"           `gives` "(NoInterval,DateSpan (Just 2008-08-01) (Just 2008-10-01))"
-    "aug to oct"                `gives` "(NoInterval,DateSpan (Just 2008-08-01) (Just 2008-10-01))"
-    "every 3 days in aug"       `gives` "(Days 3,DateSpan (Just 2008-08-01) (Just 2008-09-01))"
-    "daily from aug"            `gives` "(Days 1,DateSpan (Just 2008-08-01) Nothing)"
-    "every week to 2009"        `gives` "(Weeks 1,DateSpan Nothing (Just 2009-01-01))"
+    "from aug to oct"           `gives` "(NoInterval,DateSpan \"Just 2008-08-01\" \"Just 2008-10-01\")"
+    "aug to oct"                `gives` "(NoInterval,DateSpan \"Just 2008-08-01\" \"Just 2008-10-01\")"
+    "every 3 days in aug"       `gives` "(Days 3,DateSpan \"Just 2008-08-01\" \"Just 2008-09-01\")"
+    "daily from aug"            `gives` "(Days 1,DateSpan \"Just 2008-08-01\" \"Nothing\")"
+    "every week to 2009"        `gives` "(Weeks 1,DateSpan \"Nothing\" \"Just 2009-01-01\")"
 
   ,"splitSpan" ~: do
     let gives (interval, span) = (splitSpan interval span `is`)
diff --git a/hledger-lib/Hledger/Data/Types.hs b/hledger-lib/Hledger/Data/Types.hs
index fc75862c8..4ef19d8dc 100644
--- a/hledger-lib/Hledger/Data/Types.hs
+++ b/hledger-lib/Hledger/Data/Types.hs
@@ -31,7 +31,7 @@ type SmartDate = (String,String,String)
 
 data WhichDate = PrimaryDate | SecondaryDate deriving (Eq,Show)
 
-data DateSpan = DateSpan (Maybe Day) (Maybe Day) deriving (Eq,Show,Ord,Data,Typeable)
+data DateSpan = DateSpan (Maybe Day) (Maybe Day) deriving (Eq,Ord,Data,Typeable)
 
 data Interval = NoInterval
               | Days Int | Weeks Int | Months Int | Quarters Int | Years Int