Balance Assignments and accounts resetting (#438)

* Changed behavior of `readJournalFiles` to be identical to `readJournalFile` for singleton lists

* Balance Assertions have to be simple Amounts

* Add 'isAssignment' and 'assignmentPostings' to Hledger.Data.Posting and Transaction

* Implemented 'balanceTransactionUpdate', a more general version of 'balanceTransaction' that takes an update function

* Fixed test cases.

* Implemented balance assignment ("resetting a balance")

* Add assertions to show function

* updated the comments

* numbering is not needed in journalCheckBalanceAssertions

* remove prices before balance checks

* rename functions

hledger-lib/Hledger/Data/Amount.hs

@@ -82,7 +82,10 @@ module Hledger.Data.Amount (
   costOfMixedAmount,
   divideMixedAmount,
   averageMixedAmounts,
+  isNegativeAmount,
   isNegativeMixedAmount,
+  isZeroAmount,
+  isReallyZeroAmount,
   isZeroMixedAmount,
   isReallyZeroMixedAmount,
   isReallyZeroMixedAmountCost,

hledger-lib/Hledger/Data/Journal.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE Rank2Types #-}
 {-# LANGUAGE StandaloneDeriving, OverloadedStrings #-}
 {-|
 
@@ -61,7 +62,13 @@ module Hledger.Data.Journal (
   tests_Hledger_Data_Journal,
 )
 where
+import Control.Arrow
 import Control.Monad
+import Control.Monad.Except
+import qualified Control.Monad.Reader as R
+import Control.Monad.ST
+import Data.Array.ST
+import qualified Data.HashTable.ST.Cuckoo as HT
 import Data.List
 -- import Data.Map (findWithDefault)
 import Data.Maybe
@@ -463,8 +470,8 @@ journalApplyAliases aliases j@Journal{jtxns=ts} =
 -- check balance assertions.
 journalFinalise :: ClockTime -> FilePath -> Text -> Bool -> ParsedJournal -> Either String Journal
 journalFinalise t path txt assrt j@Journal{jfiles=fs} = do
-  (journalNumberAndTieTransactions <$>
+  (journalTieTransactions <$>
-    (journalBalanceTransactions $
+    (journalBalanceTransactions assrt $
     journalApplyCommodityStyles $
     j{ jfiles        = (path,txt) : reverse fs
      , jlastreadtime = t
@@ -473,7 +480,6 @@ journalFinalise t path txt assrt j@Journal{jfiles=fs} = do
      , jperiodictxns = reverse $ jperiodictxns j -- NOTE: see addPeriodicTransaction
      , jmarketprices = reverse $ jmarketprices j -- NOTE: see addMarketPrice
      }))
-  >>= if assrt then journalCheckBalanceAssertions else return
 
 journalNumberAndTieTransactions = journalTieTransactions . journalNumberTransactions
 
@@ -494,94 +500,208 @@ journalUntieTransactions t@Transaction{tpostings=ps} = t{tpostings=map (\p -> p{
 -- | Check any balance assertions in the journal and return an error
 -- message if any of them fail.
 journalCheckBalanceAssertions :: Journal -> Either String Journal
-journalCheckBalanceAssertions j = do
+journalCheckBalanceAssertions j =
-  let postingsByAccount = groupBy (\p1 p2 -> paccount p1 == paccount p2) $
+  runST $ journalBalanceTransactionsST True j
-                          sortBy (comparing paccount) $
+  (return ()) (\_ _ -> return ()) (const $ return j) -- noops
-                          journalPostings j
-  forM_ postingsByAccount checkBalanceAssertionsForAccount
-  Right j
 
--- Check any balance assertions in this sequence of postings to a single account.
-checkBalanceAssertionsForAccount :: [Posting] -> Either String ()
-checkBalanceAssertionsForAccount ps
-  | null errs = Right ()
-  | otherwise = Left $ head errs
-  where
-    errs = fst $
-           foldl' checkBalanceAssertion ([],nullmixedamt) $
-           splitAssertions $
-           sortBy (comparing postingDate) ps
 
--- Given a starting balance, accumulated errors, and a non-null sequence of
+-- | Check a posting's balance assertion and return an error if it
--- postings to a single account with a balance assertion in the last:
+-- fails.
--- check that the final balance matches the balance assertion.
+checkBalanceAssertion :: Posting -> MixedAmount -> Either String ()
--- If it does, return the new balance, otherwise add an error to the
+checkBalanceAssertion p@Posting{ pbalanceassertion = Just ass} amt
--- error list. Intended to be called from a fold.
+  | isReallyZeroAmount diff = Right ()
-checkBalanceAssertion :: ([String],MixedAmount) -> [Posting] -> ([String],MixedAmount)
+  | True    = Left err
-checkBalanceAssertion (errs,startbal) ps
+    where assertedcomm = acommodity ass
-  | null ps = (errs,startbal)
+          actualbal = fromMaybe nullamt $ find ((== assertedcomm) . acommodity) (amounts amt)
-  | isNothing $ pbalanceassertion p = (errs,startbal)
+          diff = ass - actualbal
-  | iswrong = (errs++[err], finalfullbal)
+          diffplus | isNegativeAmount diff == False = "+"
-  | otherwise = (errs,finalfullbal)
+                   | otherwise = ""
-  where
+          err = printf (unlines
-    p = last ps
+                        [ "balance assertion error%s",
-    Just assertedbal = pbalanceassertion p
+                          "after posting:",
-    assertedcomm = maybe "" acommodity $ headMay $ amounts assertedbal
+                          "%s",
-    finalfullbal = sum $ [startbal] ++ map pamount (dbg2 "ps" ps)
+                          "balance assertion details:",
-    finalsinglebal = filterMixedAmount (\a -> acommodity a == assertedcomm) finalfullbal
+                          "date:       %s",
-    actualbal = finalsinglebal -- just check the single-commodity balance, like Ledger; maybe add ==FULLBAL later
+                          "account:    %s",
-    iswrong = dbg2 debugmsg $
+                          "commodity:  %s",
-      not (isReallyZeroMixedAmount (actualbal - assertedbal))
+                          "calculated: %s",
-      -- bal' /= assertedbal  -- MixedAmount's Eq instance currently gets confused by different precisions
+                          "asserted:   %s (difference: %s)"
-      where
+                        ])
-        debugmsg = "assertions: on " ++ show (postingDate p) ++ " balance of " ++ show assertedcomm
+            (case ptransaction p of
-                    ++ " in " ++ T.unpack (paccount p) ++ " should be " ++ show assertedbal
+               Nothing -> ":" -- shouldn't happen
-    diff = assertedbal - actualbal
+               Just t ->  printf " in \"%s\" (line %d, column %d):\nin transaction:\n%s"
-    diffplus | isNegativeMixedAmount diff == Just False = "+"
+                          f l c (chomp $ show t) :: String
-             | otherwise = ""
+                 where GenericSourcePos f l c = tsourcepos t)
-    err = printf (unlines [
+            (showPostingLine p)
-                      "balance assertion error%s",
+            (showDate $ postingDate p)
-                      "after posting:",
+            (T.unpack $ paccount p) -- XXX pack
-                      "%s",
+            assertedcomm
-                      "balance assertion details:",
+            (showAmount actualbal)
-                      "date:       %s",
+            (showAmount ass)
-                      "account:    %s",
+            (diffplus ++ showAmount diff)
-                      "commodity:  %s",
+checkBalanceAssertion _ _ = Right ()
-                      "calculated: %s",
-                      "asserted:   %s (difference: %s)"
-                      ])
-                 (case ptransaction p of
-                    Nothing -> ":" -- shouldn't happen
-                    Just t ->  printf " in \"%s\" (line %d, column %d):\nin transaction:\n%s" f l c (chomp $ show t) :: String
-                      where GenericSourcePos f l c = tsourcepos t)
-                 (showPostingLine p)
-                 (showDate $ postingDate p)
-                 (T.unpack $ paccount p) -- XXX pack
-                 assertedcomm
-                 (showMixedAmount finalsinglebal)
-                 (showMixedAmount assertedbal)
-                 (diffplus ++ showMixedAmount diff)
 
--- Given a sequence of postings to a single account, split it into
+-- | Environment for 'CurrentBalancesModifier'
--- sub-sequences consisting of ordinary postings followed by a single
+data Env s = Env { eBalances :: HT.HashTable s AccountName MixedAmount
--- balance-asserting posting. Postings not followed by a balance
+                 , eStoreTx :: Transaction -> ST s ()
--- assertion are discarded.
+                 , eAssrt :: Bool
-splitAssertions :: [Posting] -> [[Posting]]
+                 , eStyles :: Maybe (M.Map CommoditySymbol AmountStyle) }
-splitAssertions ps
+
-  | null rest = []
+-- | Monad transformer stack with a reference to a mutable hashtable
-  | otherwise = (ps'++[head rest]):splitAssertions (tail rest)
+-- of current account balances and a mutable array of finished
-  where
+-- transactions in original parsing order.
-    (ps',rest) = break (isJust . pbalanceassertion) ps
+type CurrentBalancesModifier s = R.ReaderT (Env s) (ExceptT String (ST s))
 
 -- | Fill in any missing amounts and check that all journal transactions
 -- balance, or return an error message. This is done after parsing all
 -- amounts and applying canonical commodity styles, since balancing
 -- depends on display precision. Reports only the first error encountered.
-journalBalanceTransactions :: Journal -> Either String Journal
+journalBalanceTransactions :: Bool -> Journal -> Either String Journal
-journalBalanceTransactions j@Journal{jtxns=ts, jinferredcommodities=ss} =
+journalBalanceTransactions assrt j =
-  case sequence $ map balance ts of Right ts' -> Right j{jtxns=ts'}
+  runST $ journalBalanceTransactionsST assrt (journalNumberTransactions j)
-                                    Left e    -> Left e
+  (newArray_ (1, genericLength $ jtxns j)
-      where balance = balanceTransaction (Just ss)
+   :: forall s. ST s (STArray s Integer Transaction))
+  (\arr tx -> writeArray arr (tindex tx) tx)
+  $ fmap (\txns -> j{ jtxns = txns}) . getElems
+
+
+-- | Generalization used in the definition of
+-- 'journalBalanceTransactionsST and 'journalCheckBalanceAssertions'
+journalBalanceTransactionsST ::
+  Bool
+  -> Journal
+  -> ST s txns
+  -- ^ creates transaction store
+  -> (txns -> Transaction -> ST s ())
+  -- ^ "store" operation
+  -> (txns -> ST s a)
+  -- ^ calculate result from transactions
+  -> ST s (Either String a)
+journalBalanceTransactionsST assrt j createStore storeIn extract =
+  runExceptT $ do
+    bals <- lift $ HT.newSized size
+    txStore <- lift $ createStore
+    flip R.runReaderT (Env bals (storeIn txStore) assrt $
+                       Just $ jinferredcommodities j) $ do
+      dated <- fmap snd . sortBy (comparing fst) . concat
+             <$> mapM discriminateByDate (jtxns j)
+      mapM checkInferAndRegisterAmounts dated
+    lift $ extract txStore
+  where size = genericLength $ journalPostings j
+
+-- | This converts a transaction into a list of objects whose dates
+-- have to be considered when checking balance assertions and handled
+-- by 'checkInferAndRegisterAmounts'.
+--
+-- Transaction without balance assignments can be balanced and stored
+-- immediately and their (possibly) dated postings are returned.
+--
+-- Transaction with balance assignments are only supported if no
+-- posting has a 'pdate' value. Supported transactions will be
+-- returned unchanged and balanced and stored later in 'checkInferAndRegisterAmounts'.
+discriminateByDate :: Transaction
+  -> CurrentBalancesModifier s [(Day, Either Posting Transaction)]
+discriminateByDate tx
+  | null (assignmentPostings tx) = do
+      styles <- R.reader $ eStyles
+      balanced <- lift $ ExceptT $ return
+        $ balanceTransaction styles tx
+      storeTransaction balanced
+      return $ fmap (postingDate &&& (Left . removePrices))
+        $ tpostings $ balanced
+  | True                         = do
+      when (any (isJust . pdate) $ tpostings tx) $
+        throwError $ unlines $
+        ["Not supported: Transactions with balance assignments "
+        ,"AND dated postings without amount:\n"
+        , showTransaction tx]
+      return [(tdate tx, Right
+                $ tx { tpostings = removePrices <$> tpostings tx })]
+
+-- | This function takes different objects describing changes to
+-- account balances on a single day. It can handle either a single
+-- posting (from an already balanced transaction without assigments)
+-- or a whole transaction with assignments (which is required to no
+-- posting with pdate set.).
+--
+-- For a single posting, there is not much to do. Only add its amount
+-- to its account and check the assertion, if there is one. This
+-- functionality is provided by 'addAmountAndCheckBalance'.
+--
+-- For a whole transaction, it loops over all postings, and performs
+-- 'addAmountAndCheckBalance', if there is an amount. If there is no
+-- amount, the amount is inferred by the assertion or left empty if
+-- there is no assertion. Then, the transaction is balanced, the
+-- inferred amount added to the balance (all in
+-- 'balanceTransactionUpdate') and the resulting transaction with no
+-- missing amounts is stored in the array, for later retrieval.
+--
+-- Again in short:
+--
+-- 'Left Posting': Check the balance assertion and update the
+--  account balance. If the amount is empty do nothing.  this can be
+--  the case e.g. for virtual postings
+--
+-- 'Right Transaction': Loop over all postings, infer their amounts
+-- and then balance and store the transaction.
+checkInferAndRegisterAmounts :: Either Posting Transaction
+                             -> CurrentBalancesModifier s ()
+checkInferAndRegisterAmounts (Left p) =
+  void $ addAmountAndCheckBalance return p
+checkInferAndRegisterAmounts (Right oldTx) = do
+  let ps = tpostings oldTx
+  styles <- R.reader $ eStyles
+  newPostings <- forM ps $ addAmountAndCheckBalance inferFromAssignment
+  storeTransaction =<< balanceTransactionUpdate
+    (fmap void . addToBalance) styles oldTx { tpostings = newPostings }
+  where
+    inferFromAssignment :: Posting -> CurrentBalancesModifier s Posting
+    inferFromAssignment p = maybe (return p)
+      (fmap (\a -> p { pamount = a }) . setBalance (paccount p))
+      $ pbalanceassertion p
+
+-- | Adds a posting's amonut to the posting's account balance and
+-- checks a possible balance assertion. If there is no amount, it runs
+-- the supplied fallback action.
+addAmountAndCheckBalance :: (Posting -> CurrentBalancesModifier s Posting)
+            -- ^ action to execute, if posting has no amount
+            -> Posting
+            -> CurrentBalancesModifier s Posting
+addAmountAndCheckBalance _ p | hasAmount p = do
+  newAmt <- addToBalance (paccount p) $ pamount p
+  assrt <- R.reader eAssrt
+  lift $ when assrt $ ExceptT $ return
+    $ checkBalanceAssertion p newAmt
+  return p
+addAmountAndCheckBalance fallback p = fallback p
+
+-- | Sets an account's balance to a given amount and returns the
+-- difference of new and old amount
+setBalance :: AccountName -> Amount -> CurrentBalancesModifier s MixedAmount
+setBalance acc amt = liftModifier $ \Env{ eBalances = bals } -> do
+  old <- HT.lookup bals acc
+  let new = Mixed $ (amt :) $ maybe []
+        (filter ((/= acommodity amt) . acommodity) . amounts) old
+  HT.insert bals acc new
+  return $ maybe new (new -) old
+
+-- | Adds an amount to an account's balance and returns the resulting
+-- balance
+addToBalance :: AccountName -> MixedAmount -> CurrentBalancesModifier s MixedAmount
+addToBalance acc amt = liftModifier $ \Env{ eBalances = bals } -> do
+  new <- maybe amt (+ amt) <$> HT.lookup bals acc
+  HT.insert bals acc new
+  return new
+
+-- | Stores a transaction in the transaction array in original parsing
+-- order.
+storeTransaction :: Transaction -> CurrentBalancesModifier s ()
+storeTransaction tx = liftModifier $ ($tx) . eStoreTx
+
+-- | Helper function
+liftModifier :: (Env s -> ST s a) -> CurrentBalancesModifier s a
+liftModifier f = R.ask >>= lift . lift . f
+
 
 -- | Choose and apply a consistent display format to the posting
 -- amounts in each commodity. Each commodity's format is specified by
@@ -792,7 +912,7 @@ abspat pat = if isnegativepat pat then drop (length negateprefix) pat else pat
 --     liabilities:debts  $1
 --     assets:bank:checking
 --
-Right samplejournal = journalBalanceTransactions $
+Right samplejournal = journalBalanceTransactions False $
          nulljournal
          {jtxns = [
            txnTieKnot $ Transaction {

hledger-lib/Hledger/Data/Posting.hs

@@ -20,10 +20,12 @@ module Hledger.Data.Posting (
   isVirtual,
   isBalancedVirtual,
   isEmptyPosting,
+  isAssignment,
   hasAmount,
   postingAllTags,
   transactionAllTags,
   relatedPostings,
+  removePrices,
   -- * date operations
   postingDate,
   postingDate2,
@@ -117,12 +119,20 @@ isBalancedVirtual p = ptype p == BalancedVirtualPosting
 hasAmount :: Posting -> Bool
 hasAmount = (/= missingmixedamt) . pamount
 
+isAssignment :: Posting -> Bool
+isAssignment p = not (hasAmount p) && isJust (pbalanceassertion p)
+
 accountNamesFromPostings :: [Posting] -> [AccountName]
 accountNamesFromPostings = nub . map paccount
 
 sumPostings :: [Posting] -> MixedAmount
 sumPostings = sum . map pamount
 
+-- | Remove all prices of a posting
+removePrices :: Posting -> Posting
+removePrices p = p{ pamount = Mixed $ remove <$> amounts (pamount p) }
+  where remove a = a { aprice = NoPrice }
+
 -- | Get a posting's (primary) date - it's own primary date if specified,
 -- otherwise the parent transaction's primary date, or the null date if
 -- there is no parent transaction.

hledger-lib/Hledger/Data/Transaction.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE FlexibleContexts #-}
 {-|
 
 A 'Transaction' represents a movement of some commodity(ies) between two
@@ -19,6 +20,7 @@ module Hledger.Data.Transaction (
   showAccountName,
   hasRealPostings,
   realPostings,
+  assignmentPostings,
   virtualPostings,
   balancedVirtualPostings,
   transactionsPostings,
@@ -29,6 +31,7 @@ module Hledger.Data.Transaction (
   -- * arithmetic
   transactionPostingBalances,
   balanceTransaction,
+  balanceTransactionUpdate,
   -- * rendering
   showTransaction,
   showTransactionUnelided,
@@ -39,6 +42,8 @@ module Hledger.Data.Transaction (
 )
 where
 import Data.List
+import Control.Monad.Except
+import Control.Monad.Identity
 import Data.Maybe
 import Data.Text (Text)
 import qualified Data.Text as T
@@ -185,8 +190,8 @@ postingAsLines elideamount onelineamounts ps p =
     postinglines
     ++ newlinecomments
   where
-    postinglines = map rstrip $ lines $ concatTopPadded [account, "  ", amount, samelinecomment]
+    postinglines = map rstrip $ lines $ concatTopPadded [account, "  ", amount, assertion, samelinecomment]
-
+    assertion = maybe "" ((" = " ++) . showAmount) $ pbalanceassertion p
     account =
       indent $
         showstatus p ++ fitString (Just acctwidth) Nothing False True (showAccountName Nothing (ptype p) (paccount p))
@@ -260,6 +265,9 @@ hasRealPostings = not . null . realPostings
 realPostings :: Transaction -> [Posting]
 realPostings = filter isReal . tpostings
 
+assignmentPostings :: Transaction -> [Posting]
+assignmentPostings = filter isAssignment . tpostings
+
 virtualPostings :: Transaction -> [Posting]
 virtualPostings = filter isVirtual . tpostings
 
@@ -292,25 +300,41 @@ isTransactionBalanced styles t =
 -- amount or conversion price(s), or return an error message.
 -- Balancing is affected by commodity display precisions, so those can
 -- (optionally) be provided.
-balanceTransaction :: Maybe (Map.Map CommoditySymbol AmountStyle) -> Transaction -> Either String Transaction
+-- 
-balanceTransaction styles t =
+-- this fails for example, if there are several missing amounts
-  case inferBalancingAmount t of
+-- (possibly with balance assignments)
-    Left err -> Left err
+balanceTransaction :: Maybe (Map.Map CommoditySymbol AmountStyle)
-    Right t' -> let t'' = inferBalancingPrices t'
+                   -> Transaction -> Either String Transaction
-                in if isTransactionBalanced styles t''
+balanceTransaction stylemap = runIdentity . runExceptT
-                   then Right $ txnTieKnot t''
+  . balanceTransactionUpdate (\_ _ -> return ()) stylemap
-                   else Left $ printerr $ nonzerobalanceerror t''
+
-     where
+
-      printerr s = intercalate "\n" [s, showTransactionUnelided t]
+-- | More general version of 'balanceTransaction' that takes an update
-      nonzerobalanceerror :: Transaction -> String
+-- function
-      nonzerobalanceerror t = printf "could not balance this transaction (%s%s%s)" rmsg sep bvmsg
+balanceTransactionUpdate :: MonadError String m
-          where
+  => (AccountName -> MixedAmount -> m ())
-            (rsum, _, bvsum) = transactionPostingBalances t
+     -- ^ update function
-            rmsg | isReallyZeroMixedAmountCost rsum = ""
+  -> Maybe (Map.Map CommoditySymbol AmountStyle)
-                 | otherwise = "real postings are off by " ++ showMixedAmount (costOfMixedAmount rsum)
+  -> Transaction -> m Transaction
-            bvmsg | isReallyZeroMixedAmountCost bvsum = ""
+balanceTransactionUpdate update styles t =
-                  | otherwise = "balanced virtual postings are off by " ++ showMixedAmount (costOfMixedAmount bvsum)
+  finalize =<< inferBalancingAmount update t
-            sep = if not (null rmsg) && not (null bvmsg) then "; " else "" :: String
+  where
+    finalize t' = let t'' = inferBalancingPrices t'
+                  in if isTransactionBalanced styles t''
+                     then return $ txnTieKnot t''
+                     else throwError $ printerr $ nonzerobalanceerror t''
+    printerr s = intercalate "\n" [s, showTransactionUnelided t]
+    nonzerobalanceerror :: Transaction -> String
+    nonzerobalanceerror t = printf "could not balance this transaction (%s%s%s)" rmsg sep bvmsg
+        where
+          (rsum, _, bvsum) = transactionPostingBalances t
+          rmsg | isReallyZeroMixedAmountCost rsum = ""
+               | otherwise = "real postings are off by "
+                 ++ showMixedAmount (costOfMixedAmount rsum)
+          bvmsg | isReallyZeroMixedAmountCost bvsum = ""
+                | otherwise = "balanced virtual postings are off by "
+                  ++ showMixedAmount (costOfMixedAmount bvsum)
+          sep = if not (null rmsg) && not (null bvmsg) then "; " else "" :: String
 
 -- | Infer up to one missing amount for this transactions's real postings, and
 -- likewise for its balanced virtual postings, if needed; or return an error
@@ -319,22 +343,31 @@ balanceTransaction styles t =
 -- We can infer a missing amount when there are multiple postings and exactly
 -- one of them is amountless. If the amounts had price(s) the inferred amount
 -- have the same price(s), and will be converted to the price commodity.
--- 
+inferBalancingAmount :: MonadError String m
-inferBalancingAmount :: Transaction -> Either String Transaction
+                     => (AccountName -> MixedAmount -> m ())
-inferBalancingAmount t@Transaction{tpostings=ps}
+                     -- ^ update function
+                     -> Transaction -> m Transaction
+inferBalancingAmount update t@Transaction{tpostings=ps}
   | length amountlessrealps > 1
-      = Left $ printerr "could not balance this transaction - can't have more than one real posting with no amount (remember to put 2 or more spaces before amounts)"
+      = throwError $ printerr "could not balance this transaction - can't have more than one real posting with no amount (remember to put 2 or more spaces before amounts)"
   | length amountlessbvps > 1
-      = Left $ printerr "could not balance this transaction - can't have more than one balanced virtual posting with no amount (remember to put 2 or more spaces before amounts)"
+      = throwError $ printerr "could not balance this transaction - can't have more than one balanced virtual posting with no amount (remember to put 2 or more spaces before amounts)"
   | otherwise
-      = Right t{tpostings=map inferamount ps}
+      = do postings <- mapM inferamount ps
+           return t{tpostings=postings}
   where
     printerr s = intercalate "\n" [s, showTransactionUnelided t]
-    ((amountfulrealps, amountlessrealps), realsum) = (partition hasAmount (realPostings t), sum $ map pamount amountfulrealps)
+    ((amountfulrealps, amountlessrealps), realsum) =
-    ((amountfulbvps, amountlessbvps), bvsum)       = (partition hasAmount (balancedVirtualPostings t), sum $ map pamount amountfulbvps)
+      (partition hasAmount (realPostings t), sum $ map pamount amountfulrealps)
-    inferamount p@Posting{ptype=RegularPosting}         | not (hasAmount p) = p{pamount=costOfMixedAmount (-realsum)}
+    ((amountfulbvps, amountlessbvps), bvsum)       =
-    inferamount p@Posting{ptype=BalancedVirtualPosting} | not (hasAmount p) = p{pamount=costOfMixedAmount (-bvsum)}
+      (partition hasAmount (balancedVirtualPostings t), sum $ map pamount amountfulbvps)
-    inferamount p = p
+    inferamount p@Posting{ptype=RegularPosting}
+     | not (hasAmount p) = updateAmount p realsum
+    inferamount p@Posting{ptype=BalancedVirtualPosting}
+     | not (hasAmount p) = updateAmount p bvsum
+    inferamount p = return p
+    updateAmount p amt = update (paccount p) amt' >> return p { pamount=amt' }
+      where amt' = costOfMixedAmount (-amt)
 
 -- | Infer prices for this transaction's posting amounts, if needed to make
 -- the postings balance, and if possible. This is done once for the real

hledger-lib/Hledger/Data/Types.hs

@@ -198,7 +198,7 @@ data Posting = Posting {
       pcomment          :: Text,              -- ^ this posting's comment lines, as a single non-indented multi-line string
       ptype             :: PostingType,
       ptags             :: [Tag],             -- ^ tag names and values, extracted from the comment
-      pbalanceassertion :: Maybe MixedAmount, -- ^ optional: the expected balance in the account after this posting
+      pbalanceassertion :: Maybe Amount,      -- ^ optional: the expected balance in this commodity in the account after this posting
       ptransaction      :: Maybe Transaction  -- ^ this posting's parent transaction (co-recursive types).
                                               -- Tying this knot gets tedious, Maybe makes it easier/optional.
     } deriving (Typeable,Data,Generic)

hledger-lib/Hledger/Read/Common.hs

@@ -427,14 +427,14 @@ priceamountp =
             return $ UnitPrice a))
          <|> return NoPrice
 
-partialbalanceassertionp :: Monad m => JournalStateParser m (Maybe MixedAmount)
+partialbalanceassertionp :: Monad m => JournalStateParser m (Maybe Amount)
 partialbalanceassertionp =
     try (do
           lift (many spacenonewline)
           char '='
           lift (many spacenonewline)
           a <- amountp -- XXX should restrict to a simple amount
-          return $ Just $ Mixed [a])
+          return $ Just $ a)
          <|> return Nothing
 
 -- balanceassertion :: Monad m => TextParser m (Maybe MixedAmount)

hledger-lib/Hledger/Reports/BalanceReport.hs

@@ -387,7 +387,7 @@ tests_balanceReport =
  ]
 
 Right samplejournal2 =
-  journalBalanceTransactions
+  journalBalanceTransactions False
     nulljournal{
       jtxns = [
         txnTieKnot Transaction{

hledger-lib/hledger-lib.cabal

@@ -71,6 +71,7 @@ library
     , deepseq
     , directory
     , filepath
+    , hashtables >= 1.2
     , megaparsec >=5.0 && < 5.2
     , mtl
     , mtl-compat
@@ -168,6 +169,7 @@ test-suite doctests
     , deepseq
     , directory
     , filepath
+    , hashtables >= 1.2
     , megaparsec >=5.0 && < 5.2
     , mtl
     , mtl-compat
@@ -256,6 +258,7 @@ test-suite hunittests
     , deepseq
     , directory
     , filepath
+    , hashtables >= 1.2
     , megaparsec >=5.0 && < 5.2
     , mtl
     , mtl-compat

hledger-lib/package.yaml

@@ -52,6 +52,7 @@ dependencies:
 - deepseq
 - directory
 - filepath
+- hashtables >= 1.2
 - megaparsec >=5.0 && < 5.2
 - mtl
 - mtl-compat

tests/cli/multiple-files.test

@@ -43,7 +43,7 @@ hledger print -f personal.journal -f business.journal -f alias.journal -f person
 
 
 # 3. files can be of different formats
-hledger print -f personal.journal -f a.timeclock -f b.timedot
+hledger print -f personal.journal -f ../journal/a.timeclock -f ../journal/b.timedot
 >>>
 2014/01/02
     expenses:food            $1
@@ -55,6 +55,7 @@ hledger print -f personal.journal -f a.timeclock -f b.timedot
 2016/01/01 *
     (b.bb)          1.00
 
+>>>2
 >>>=0
 
 u

tests/i18n/wide-char-layout.test

@@ -31,6 +31,7 @@ hledger -f - print
     㐀:㐁:㐂:㐃:㐄             1
     㐀                        -1
 
+>>>2
 >>>=0
 
 # 2.
@@ -42,6 +43,7 @@ hledger -f chinese.journal register --width 80
                                 㐀:㐁:㐂:㐃                     -1             0
 2014/01/03 transaction 3        㐀:㐁:㐂:㐃:㐄                   1             1
                                 㐀                              -1             0
+>>>2
 >>>=0
 
 # 3.
@@ -53,6 +55,7 @@ hledger -f chinese.journal balance
                    1        㐄
 --------------------
                    0
+>>>2
 >>>=0
 
 # 4.
@@ -69,6 +72,7 @@ Balance changes in 2014:
 ----------------++-------
                 ||     0 
 
+>>>2
 >>>=0
 
 # 5.

tests/journal/balance-assertions.test

@@ -136,3 +136,175 @@ hledger -f - stats
 # >>> /Transactions/
 # >>>2
 # >>>=0
+
+# 8. resetting a balance
+hledger -f - stats
+<<<
+2013/1/1
+  a    $1.20
+  b
+
+2013/1/2
+  a           =$1.3
+  b
+
+2013/1/2
+  a           $10 =$11.3
+  b         =$-11.3
+
+>>> /Transactions/
+>>>2
+>>>=0
+
+
+# 9. Multiple assertions for an account in the same transaction.
+hledger -f - stats
+<<<
+2013/1/1
+  a    $1  =$1
+  b        =-$1
+
+2013/1/2
+  a    $1  =$2
+  b   $-1  =$-2
+
+2013/1/3
+  a    $2  = $4
+  b   $-1  = $-3
+  b   $-1  = $-4
+
+>>> /Transactions/
+>>>2
+>>>=0
+
+# 10. Multiple assertions and assignments for an account in the same transaction.
+hledger -f - stats
+<<<
+2013/1/1
+  a    $1  =$1
+  b        =-$1
+
+2013/1/3
+  a    $6  = $7
+  b   $-1  = $-2
+  b   $-1  = $-3
+  b   $-7    = $-10
+  b   $-1
+  b   $-1  = $-12
+  b
+
+2013/1/4
+  a    $0 = $7
+  b   $0   = $-7
+
+>>> /Transactions/
+>>>2
+>>>=0
+
+# 11. Assignments and virtual postings
+hledger -f - stats
+<<<
+2013/1/1
+  b
+  [a]    1$
+  (b)     = $14
+  [b]
+  a      4$
+
+
+2013/1/2
+  [a]      = $5
+  b        = $9
+
+
+
+
+>>> /Transactions/
+>>>2
+>>>=0
+# 12. Having both assignements and posting dates is not supported.
+hledger -f - stats
+<<<
+2013/1/1
+  a    $1  =$1
+  b         =$-1  ; date:2012/1/1
+
+>>>2  /Not supported/
+>>>=1
+
+# 13. Having both assignements and posting dates is not supported.
+hledger -f - stats
+<<<
+
+2013/1/1
+  a    1 = -2
+  b
+  c   = 5
+
+2014/1/1
+  a    -3 = -3  ; date:2012/1/1
+  d      = 3
+
+
+>>>2  /Not supported/
+>>>=1
+
+# 14. Posting Date
+hledger -f - stats
+<<<
+
+2011/5/5
+  [a]        = -10
+
+2013/1/1
+  a    1 = -12
+  b
+  c   = 5
+
+2014/1/1
+  a      ; date:2012/1/1
+  d     3 = 3
+
+2015/1/1
+  [a]      ; date:2011/1/1
+  [d]    10
+
+
+>>> /Transactions/
+>>>2
+>>>=0
+
+# 15. Mix different commodities
+hledger -f - stats
+<<<
+2016/1/1
+    a      $1
+    b      -1 zorkmids
+
+2016/1/2
+    a     $-1 = $0
+    b
+>>> /Transactions/
+>>>2
+>>>=0
+
+# 16. Mix different commodities and assignments
+hledger -f - stats
+<<<
+2016/1/1
+    a      $1
+    b      -1 zorkmids
+
+2016/1/4
+    [a]    = $1
+
+
+2016/1/5
+    [a]    = -1 zorkmids
+
+2016/1/2
+    a
+    b      = 0 zorkmids
+>>> /Transactions/
+>>>2
+>>>=0

tests/journal/virtual-postings.test

@@ -51,4 +51,5 @@ hledger -f- balance
                  -10  f
 --------------------
                    0
+>>>2
 >>>=0