diff --git a/Hledger/Cli/Commands/Register.hs b/Hledger/Cli/Commands/Register.hs
index a921d7909..7a67000eb 100644
--- a/Hledger/Cli/Commands/Register.hs
+++ b/Hledger/Cli/Commands/Register.hs
@@ -51,12 +51,6 @@ summarisePostings interval depth empty filterspan ps = concatMap summarisespan $
       reportspan | empty = filterspan `orDatesFrom` dataspan
                  | otherwise = dataspan
 
--- | Combine two datespans, filling any unspecified dates in the first
--- with dates from the second.
-orDatesFrom (DateSpan a1 b1) (DateSpan a2 b2) = DateSpan a b
-    where a = if isJust a1 then a1 else a2
-          b = if isJust b1 then b1 else b2
-
 -- | Date-sort and split a list of postings into three spans - postings matched
 -- by the given display expression, and the preceding and following postings.
 postingsMatchingDisplayExpr :: Maybe String -> [Posting] -> ([Posting],[Posting],[Posting])
diff --git a/hledger-lib/Hledger/Data/Commodity.hs b/hledger-lib/Hledger/Data/Commodity.hs
index b92e21eee..d2cd07bda 100644
--- a/hledger-lib/Hledger/Data/Commodity.hs
+++ b/hledger-lib/Hledger/Data/Commodity.hs
@@ -10,6 +10,8 @@ module Hledger.Data.Commodity
 where
 import Hledger.Data.Utils
 import Hledger.Data.Types
+import qualified Data.Map as Map
+import Data.Map ((!))
 
 
 nonsimplecommoditychars = "0123456789-.@;\n \""
@@ -39,3 +41,16 @@ comm sym = fromMaybe
 conversionRate :: Commodity -> Commodity -> Double
 conversionRate _ _ = 1
 
+-- | Convert a list of commodities to a map from commodity symbols to
+-- unique, display-preference-canonicalised commodities.
+canonicaliseCommodities :: [Commodity] -> Map.Map String Commodity
+canonicaliseCommodities cs =
+    Map.fromList [(s,firstc{precision=maxp}) | s <- symbols,
+                  let cs = commoditymap ! s,
+                  let firstc = head cs,
+                  let maxp = maximum $ map precision cs
+                 ]
+  where
+    commoditymap = Map.fromList [(s, commoditieswithsymbol s) | s <- symbols]
+    commoditieswithsymbol s = filter ((s==) . symbol) cs
+    symbols = nub $ map symbol cs
diff --git a/hledger-lib/Hledger/Data/Dates.hs b/hledger-lib/Hledger/Data/Dates.hs
index 78b5411f5..54cb8f15c 100644
--- a/hledger-lib/Hledger/Data/Dates.hs
+++ b/hledger-lib/Hledger/Data/Dates.hs
@@ -71,7 +71,20 @@ splitspan start next span@(DateSpan (Just b) (Just e))
 daysInSpan :: DateSpan -> Maybe Integer
 daysInSpan (DateSpan (Just d1) (Just d2)) = Just $ diffDays d2 d1
 daysInSpan _ = Nothing
+
+-- | Does the span include the given date ?
+spanContainsDate :: DateSpan -> Day -> Bool
+spanContainsDate (DateSpan Nothing Nothing)   _ = True
+spanContainsDate (DateSpan Nothing (Just e))  d = d < e
+spanContainsDate (DateSpan (Just b) Nothing)  d = d >= b
+spanContainsDate (DateSpan (Just b) (Just e)) d = d >= b && d < e
     
+-- | Combine two datespans, filling any unspecified dates in the first
+-- with dates from the second.
+orDatesFrom (DateSpan a1 b1) (DateSpan a2 b2) = DateSpan a b
+    where a = if isJust a1 then a1 else a2
+          b = if isJust b1 then b1 else b2
+
 -- | Parse a period expression to an Interval and overall DateSpan using
 -- the provided reference date, or raise an error.
 parsePeriodExpr :: Day -> String -> (Interval, DateSpan)
diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index cde7db1db..7818bd4c5 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -15,6 +15,7 @@ import Hledger.Data.Utils
 import Hledger.Data.Types
 import Hledger.Data.AccountName
 import Hledger.Data.Amount
+import Hledger.Data.Commodity (canonicaliseCommodities)
 import Hledger.Data.Dates (nulldatespan)
 import Hledger.Data.Transaction (journalTransactionWithDate)
 import Hledger.Data.Posting
@@ -268,17 +269,7 @@ journalConvertAmountsToCost j@Journal{jtxns=ts} = j{jtxns=map fixtransaction ts}
 
 -- | Get this journal's unique, display-preference-canonicalised commodities, by symbol.
 journalCanonicalCommodities :: Journal -> Map.Map String Commodity
-journalCanonicalCommodities j =
-    Map.fromList [(s,firstc{precision=maxp}) | s <- commoditysymbols,
-                  let cs = commoditymap ! s,
-                  let firstc = head cs,
-                  let maxp = maximum $ map precision cs
-                 ]
-  where
-    commoditymap = Map.fromList [(s,commoditieswithsymbol s) | s <- commoditysymbols]
-    commoditieswithsymbol s = filter ((s==) . symbol) commodities
-    commoditysymbols = nub $ map symbol commodities
-    commodities = journalAmountAndPriceCommodities j
+journalCanonicalCommodities j = canonicaliseCommodities $ journalAmountAndPriceCommodities j
 
 -- | Get all this journal's amounts' commodities, in the order parsed.
 journalAmountCommodities :: Journal -> [Commodity]
diff --git a/hledger-lib/Hledger/Data/Posting.hs b/hledger-lib/Hledger/Data/Posting.hs
index 1343ceab9..5577a9163 100644
--- a/hledger-lib/Hledger/Data/Posting.hs
+++ b/hledger-lib/Hledger/Data/Posting.hs
@@ -14,7 +14,7 @@ import Hledger.Data.Utils
 import Hledger.Data.Types
 import Hledger.Data.Amount
 import Hledger.Data.AccountName
-import Hledger.Data.Dates (nulldate)
+import Hledger.Data.Dates (nulldate, spanContainsDate)
 
 
 instance Show Posting where show = showPosting
@@ -79,10 +79,7 @@ postingCleared p = maybe False tstatus $ ptransaction p
 
 -- | Does this posting fall within the given date span ?
 isPostingInDateSpan :: DateSpan -> Posting -> Bool
-isPostingInDateSpan (DateSpan Nothing Nothing)   _ = True
-isPostingInDateSpan (DateSpan Nothing (Just e))  p = postingDate p < e
-isPostingInDateSpan (DateSpan (Just b) Nothing)  p = postingDate p >= b
-isPostingInDateSpan (DateSpan (Just b) (Just e)) p = d >= b && d < e where d = postingDate p
+isPostingInDateSpan s = spanContainsDate s . postingDate
 
 isEmptyPosting :: Posting -> Bool
 isEmptyPosting = isZeroMixedAmount . pamount