lib: flip the arguments of (divide|multiply)[Mixed]Amount (api change)

Also, start using a mapMixedAmount helper.

hledger-lib/Hledger/Data/Amount.hs

@@ -223,12 +223,12 @@ amountTotalPriceToUnitPrice
 amountTotalPriceToUnitPrice a = a
 
 -- | Divide an amount's quantity by a constant.
-divideAmount :: Amount -> Quantity -> Amount
-divideAmount a@Amount{aquantity=q} d = a{aquantity=q/d}
+divideAmount :: Quantity -> Amount -> Amount
+divideAmount n a@Amount{aquantity=q} = a{aquantity=q/n}
 
 -- | Multiply an amount's quantity by a constant.
-multiplyAmount :: Amount -> Quantity -> Amount
-multiplyAmount a@Amount{aquantity=q} d = a{aquantity=q*d}
+multiplyAmount :: Quantity -> Amount -> Amount
+multiplyAmount n a@Amount{aquantity=q} = a{aquantity=q*n}
 
 -- | Is this amount negative ? The price is ignored.
 isNegativeAmount :: Amount -> Bool
@@ -536,23 +536,27 @@ filterMixedAmountByCommodity c (Mixed as) = Mixed as'
             []   -> [nullamt{acommodity=c}]
             as'' -> [sum as'']
 
+-- | Apply a transform to a mixed amount's component 'Amount's.
+mapMixedAmount :: (Amount -> Amount) -> MixedAmount -> MixedAmount
+mapMixedAmount f (Mixed as) = Mixed $ map f as
+
 -- | Convert a mixed amount's component amounts to the commodity of their
 -- assigned price, if any.
 costOfMixedAmount :: MixedAmount -> MixedAmount
 costOfMixedAmount (Mixed as) = Mixed $ map costOfAmount as
 
 -- | Divide a mixed amount's quantities by a constant.
-divideMixedAmount :: MixedAmount -> Quantity -> MixedAmount
-divideMixedAmount (Mixed as) d = Mixed $ map (`divideAmount` d) as
+divideMixedAmount :: Quantity -> MixedAmount -> MixedAmount
+divideMixedAmount n = mapMixedAmount (divideAmount n)
 
 -- | Multiply a mixed amount's quantities by a constant.
-multiplyMixedAmount :: MixedAmount -> Quantity -> MixedAmount
-multiplyMixedAmount (Mixed as) d = Mixed $ map (`multiplyAmount` d) as
+multiplyMixedAmount :: Quantity -> MixedAmount -> MixedAmount
+multiplyMixedAmount n = mapMixedAmount (multiplyAmount n)
 
 -- | Calculate the average of some mixed amounts.
 averageMixedAmounts :: [MixedAmount] -> MixedAmount
 averageMixedAmounts [] = 0
-averageMixedAmounts as = sum as `divideMixedAmount` fromIntegral (length as)
+averageMixedAmounts as = fromIntegral (length as) `divideMixedAmount` sum as 
 
 -- | Is this mixed amount negative, if it can be normalised to a single commodity ?
 isNegativeMixedAmount :: MixedAmount -> Maybe Bool

hledger-lib/Hledger/Data/Transaction.hs

@@ -469,7 +469,7 @@ priceInferrerFor t pt = inferprice
             fromamount    = head $ filter ((==fromcommodity).acommodity) sumamounts
             tocommodity   = head $ filter (/=fromcommodity) sumcommodities
             toamount      = head $ filter ((==tocommodity).acommodity) sumamounts
-            unitprice     = toamount `divideAmount` (aquantity fromamount)
+            unitprice     = (aquantity fromamount) `divideAmount` toamount
             unitprecision = max 2 ((asprecision $ astyle $ toamount) + (asprecision $ astyle $ fromamount))
     inferprice p = p
 

hledger-lib/Hledger/Data/TransactionModifier.hs

@@ -97,7 +97,7 @@ tmPostingRuleToFunction pr =
             pramount = dbg6 "pramount" $ head $ amounts $ pamount pr
             matchedamount = dbg6 "matchedamount" $ pamount p
             unitpricedmatchedamount = dbg6 "unitpricedmatchedamount" $ mixedAmountTotalPriceToUnitPrice matchedamount
-            Mixed as = dbg6 "scaledmatchedamount" $ unitpricedmatchedamount `multiplyMixedAmount` n
+            Mixed as = dbg6 "scaledmatchedamount" $ n `multiplyMixedAmount` unitpricedmatchedamount 
           in
             case acommodity pramount of
               "" -> Mixed as

hledger-lib/Hledger/Reports/PostingsReport.hs

@@ -77,12 +77,12 @@ postingsReport opts q j = (totallabel, items)
           historical = balancetype_ opts == HistoricalBalance
           precedingsum = sumPostings precedingps
           precedingavg | null precedingps = 0
-                       | otherwise        = precedingsum `divideMixedAmount` (fromIntegral $ length precedingps)
+                       | otherwise        = divideMixedAmount (fromIntegral $ length precedingps) precedingsum
           startbal | average_ opts = if historical then precedingavg else 0
                    | otherwise     = if historical then precedingsum else 0
           startnum = if historical then length precedingps + 1 else 1
-          runningcalc | average_ opts = \i avg amt -> avg + (amt - avg) `divideMixedAmount` (fromIntegral i) -- running average
-                      | otherwise     = \_ bal amt -> bal + amt                                              -- running total
+          runningcalc | average_ opts = \i avg amt -> divideMixedAmount (fromIntegral i) avg + amt - avg  -- running average
+                      | otherwise     = \_ bal amt -> bal + amt                                           -- running total
 
 totallabel = "Total"
 

hledger/Hledger/Cli/Commands/Prices.hs

@@ -49,11 +49,11 @@ prices opts j = do
 showPrice :: MarketPrice -> String
 showPrice mp = unwords ["P", show $ mpdate mp, T.unpack . quoteCommoditySymbolIfNeeded $ mpcommodity mp, showAmountWithZeroCommodity $ mpamount mp]
 
-divideAmount' :: Amount -> Quantity -> Amount
-divideAmount' a d = a' where
-    a' = (a `divideAmount` d) { astyle = style' }
+divideAmount' :: Quantity -> Amount -> Amount
+divideAmount' n a = a' where
+    a' = (n `divideAmount` a) { astyle = style' }
     style' = (astyle a) { asprecision = precision' }
-    extPrecision = (1+) . floor . logBase 10 $ (realToFrac d :: Double)
+    extPrecision = (1+) . floor . logBase 10 $ (realToFrac n :: Double)
     precision' = extPrecision + asprecision (astyle a)
 
 invertPrice :: Amount -> Amount
@@ -63,7 +63,7 @@ invertPrice a =
         UnitPrice pa -> invertPrice
             -- normalize to TotalPrice
             a { aprice = TotalPrice pa' } where
-                pa' = (pa `divideAmount` (1 / aquantity a)) { aprice = NoPrice }
+                pa' = ((1 / aquantity a) `divideAmount` pa) { aprice = NoPrice }
         TotalPrice pa ->
             a { aquantity = aquantity pa * signum (aquantity a), acommodity = acommodity pa, aprice = TotalPrice pa' } where
                 pa' = pa { aquantity = abs $ aquantity a, acommodity = acommodity a, aprice = NoPrice, astyle = astyle a }
@@ -75,7 +75,7 @@ amountCost d a =
         UnitPrice pa -> Just
             MarketPrice { mpdate = d, mpcommodity = acommodity a, mpamount = pa }
         TotalPrice pa -> Just
-            MarketPrice { mpdate = d, mpcommodity = acommodity a, mpamount = pa `divideAmount'` abs (aquantity a) }
+            MarketPrice { mpdate = d, mpcommodity = acommodity a, mpamount = abs (aquantity a) `divideAmount'` pa }
 
 postingCosts :: Posting -> [MarketPrice]
 postingCosts p = mapMaybe (amountCost date) . amounts $ pamount p  where

hledger/Hledger/Cli/CompoundBalanceCommand.hs

@@ -187,7 +187,7 @@ compoundBalanceCommand CompoundBalanceCommandSpec{..} opts@CliOpts{reportopts_=r
               where zeros = replicate numcols nullmixedamt
             grandtotal = sum coltotals
             grandavg | null coltotals = nullmixedamt
-                     | otherwise      = grandtotal `divideMixedAmount` fromIntegral (length coltotals)
+                     | otherwise      = fromIntegral (length coltotals) `divideMixedAmount` grandtotal 
           in 
             (coltotals, grandtotal, grandavg)
       colspans =