zero amounts have no sign or commodity, and amounts with different prices are aggregated, like ledger

hledger-lib/Hledger/Data/Amount.hs

@@ -238,8 +238,7 @@ isNegativeAmount Amount{quantity=q} = q < 0
 amounts :: MixedAmount -> [Amount]
 amounts (Mixed as) = as
 
--- | Does this mixed amount appear to be zero - empty, or
+-- | Does this mixed amount appear to be zero when displayed with its given precision ?
--- containing only simple amounts which appear to be zero ?
 isZeroMixedAmount :: MixedAmount -> Bool
 isZeroMixedAmount = all isZeroAmount . amounts . normaliseMixedAmount
 
@@ -313,21 +312,19 @@ showMixedAmountOrZeroWithoutPrice a
     | isZeroMixedAmount a = "0"
     | otherwise = showMixedAmountWithoutPrice a
 
--- | Simplify a mixed amount by combining any component amounts which have
+-- | Simplify a mixed amount by removing redundancy in its component amounts, as follows:
--- the same commodity and the same price. Also removes zero amounts,
+-- 1. sum amounts which have the same commodity (ignoring their price)
--- or adds a single zero amount if there are no amounts at all.
+-- 2. remove zero amounts
+-- 3. if there are no amounts at all, add a single zero amount
 normaliseMixedAmount :: MixedAmount -> MixedAmount
 normaliseMixedAmount (Mixed as) = Mixed as''
     where 
-      as'' = map sumSamePricedAmountsPreservingPrice $ group $ sort as'
+      as'' = if null nonzeros then [nullamt] else nonzeros
-      sort = sortBy cmpsymbolandprice
+      (_,nonzeros) = partition (\a -> isReallyZeroAmount a && Mixed [a] /= missingamt) as'
-      cmpsymbolandprice a1 a2 = compare (sym a1,price a1) (sym a2,price a2)
+      as' = map sumSamePricedAmountsPreservingPrice $ group $ sort as
-      group = groupBy samesymbolandprice 
+      sort = sortBy (\a1 a2 -> compare (sym a1) (sym a2))
-      samesymbolandprice a1 a2 = (sym a1 == sym a2) && (price a1 == price a2)
+      group = groupBy (\a1 a2 -> sym a1 == sym a2)
       sym = symbol . commodity
-      as' | null nonzeros = [head $ zeros ++ [nullamt]]
-          | otherwise = nonzeros
-      (zeros,nonzeros) = partition isReallyZeroAmount as
 
 -- | Set a mixed amount's commodity to the canonicalised commodity from
 -- the provided commodity map.
@@ -427,8 +424,11 @@ missingamt = Mixed [Amount unknown{symbol="AUTO"} 0 Nothing]
 
 tests_Hledger_Data_Amount = TestList [
 
-   "showMixedAmount" ~: do
+   "showAmount" ~: do
-     showMixedAmount (Mixed [Amount dollar 0 Nothing]) `is` "$0.00"
+     showAmount (dollars 0 + pounds 0) `is` "0"
+
+  ,"showMixedAmount" ~: do
+     showMixedAmount (Mixed [Amount dollar 0 Nothing]) `is` "0"
      showMixedAmount (Mixed []) `is` "0"
      showMixedAmount missingamt `is` ""
 
@@ -458,10 +458,15 @@ tests_Hledger_Data_Amount = TestList [
              [Amount dollar 1.25 Nothing,
               Amount dollar0 (-1) Nothing,
               Amount dollar (-0.25) Nothing])
-      `is` Mixed [Amount dollar 0 Nothing]
+      `is` Mixed [Amount unknown 0 Nothing]
 
   ,"normaliseMixedAmount" ~: do
-     normaliseMixedAmount (Mixed []) ~?= Mixed [nullamt]
+     normaliseMixedAmount (Mixed []) `is` Mixed [nullamt]
+     assertBool "" $ isZeroMixedAmount $ normaliseMixedAmount (Mixed [Amount {commodity=dollar, quantity=10,    price=Nothing}
+                                                                     ,Amount {commodity=dollar, quantity=10,    price=Just (TotalPrice (Mixed [Amount {commodity=euro, quantity=7, price=Nothing}]))}
+                                                                     ,Amount {commodity=dollar, quantity=(-10), price=Nothing}
+                                                                     ,Amount {commodity=dollar, quantity=(-10), price=Just (TotalPrice (Mixed [Amount {commodity=euro, quantity=7, price=Nothing}]))}
+                                                                     ])
 
   ,"punctuatethousands 1" ~: punctuatethousands "" `is` ""
 

hledger/Hledger/Cli.hs

@@ -112,7 +112,7 @@ tests_Hledger_Cli = TestList
     ,"                 $-1    salary"
     ,"                  $1  liabilities:debts"
     ,"--------------------"
-    ,"                  $0"
+    ,"                   0"
     ]
 
    ,"balance report can be limited with --depth" ~:
@@ -122,7 +122,7 @@ tests_Hledger_Cli = TestList
     ,"                 $-2  income"
     ,"                  $1  liabilities"
     ,"--------------------"
-    ,"                  $0"
+    ,"                   0"
     ]
     
    ,"balance report with account pattern o" ~:
@@ -167,7 +167,7 @@ tests_Hledger_Cli = TestList
     ,"                 $-1    salary"
     ,"                  $1  liabilities:debts"
     ,"--------------------"
-    ,"                  $0"
+    ,"                   0"
     ]
 
    ,"balance report with unmatched parent of two matched subaccounts" ~: 
@@ -216,7 +216,7 @@ tests_Hledger_Cli = TestList
     ([SubTotal,Empty], ["assets"]) `gives`
     ["                 $-1  assets"
     ,"                  $1    bank"
-    ,"                  $0      checking"
+    ,"                   0      checking"
     ,"                  $1      saving"
     ,"                 $-2    cash"
     ,"--------------------"
@@ -236,7 +236,7 @@ tests_Hledger_Cli = TestList
         ["                $500  a:b"
         ,"               $-500  c:d"
         ,"--------------------"
-        ,"                  $0"
+        ,"                   0"
         ]
 
    ,"balance report elides zero-balance root account(s)" ~: do

tests/amount-layout-vertical.test

@@ -43,7 +43,7 @@ bin/hledger -f - balance
               EUR -1   
               USD -1  c
 --------------------
-               EUR 0
+                   0
 >>>=0
 
 # 4. mixed amounts with prices

tests/commodities.test

@@ -30,5 +30,5 @@ bin/hledger -f- balance
    10 "DE0002635307"  a
   -10 "DE0002635307"  b
 --------------------
-    0 "DE0002635307"
+                   0
 >>>=0

tests/eliding-balance.test

@@ -16,15 +16,13 @@ bin/hledger -f - balance
 # 2. Two commodities. As above, and the final total should be a single commodityless zero.
 bin/hledger -f - balance
 <<<
-2010/04/01 tr1
+2010/1/1
   a   16$ @@ 10€
   b   -10€
-
+2010/1/2
-2010/04/02 tr2
   a   -16$
   b   10€ @@ 16$
 >>>
 --------------------
                    0
 >>>=0
-

tests/precision.test

@@ -49,7 +49,7 @@ bin/hledger -f - balance --no-total --cost --empty
    a  1C @ $1.0049
    a  $-1.00
 >>>
-               $0.00  a
+                   0  a
 >>>=0
 
 # 5. avamk's 2011/1/19 example
@@ -62,7 +62,7 @@ bin/hledger -f - -B bal
             $3266.32  assets:investment:ACME
            $-3266.32  equity:opening balances
 --------------------
-               $0.00
+                   0
 >>>=0
 # hledger 0.14pre: precision=2, presumably from price
 #            $3266.32  assets:investment:ACME
@@ -91,7 +91,7 @@ D $1000.0
             $3266.32  assets:investment:ACME
            $-3266.32  equity:opening balances
 --------------------
-               $0.00
+                   0
 >>>=0
 ### hledger 0.14pre: precision=2, presumably from price, ignores D
 ###            $3266.32  assets:investment:ACME

tests/prices.test

@@ -132,7 +132,7 @@ bin/hledger -f - balance -B
                $-135  assets
                 $135  expenses:foreign currency
 --------------------
-                  $0
+                   0
 >>>=0
 # 10. transaction in two commodities should balance out properly
 bin/hledger -f - balance --basis
@@ -144,6 +144,5 @@ bin/hledger -f - balance --basis
                  16$  a
                 -16$  b
 --------------------
-                  0$
+                   0
-
 >>>=0

tests/sample-balance-depth.test

@@ -5,4 +5,4 @@ bin/hledger -f data/sample.journal balance --depth 1
                  $-2  income
                   $1  liabilities
 --------------------
-                  $0
+                   0

tests/sample-balance.test

@@ -11,4 +11,4 @@ bin/hledger -f data/sample.journal balance
                  $-1    salary
                   $1  liabilities:debts
 --------------------
-                  $0
+                   0

tests/unicode-balance.test

@@ -7,4 +7,4 @@ bin/hledger -f - balance
               10 руб  τράπεζα
              -10 руб  नकद
 --------------------
-               0 руб
+                   0