lib: clarify zero-checking function names

isZeroAmount                -> amountLooksZero
isReallyZeroAmount          -> amountIsZero
isZeroMixedAmount           -> mixedAmountLooksZero
isReallyZeroMixedAmount     -> mixedAmountIsZero
isReallyZeroMixedAmountCost dropped

hledger-lib/Hledger/Data/Amount.hs

@@ -63,6 +63,8 @@ module Hledger.Data.Amount (
   -- ** arithmetic
   costOfAmount,
   amountToCost,
+  amountIsZero,
+  amountLooksZero,
   divideAmount,
   multiplyAmount,
   divideAmountAndPrice,
@@ -110,11 +112,8 @@ module Hledger.Data.Amount (
   averageMixedAmounts,
   isNegativeAmount,
   isNegativeMixedAmount,
-  isZeroAmount,
-  isReallyZeroAmount,
-  isZeroMixedAmount,
-  isReallyZeroMixedAmount,
-  isReallyZeroMixedAmountCost,
+  mixedAmountIsZero,
+  mixedAmountLooksZero,
   mixedAmountTotalPriceToUnitPrice,
   -- ** rendering
   styleMixedAmount,
@@ -269,14 +268,14 @@ isNegativeAmount Amount{aquantity=q} = q < 0
 
 digits = "123456789" :: String
 
--- | Does this amount appear to be zero when displayed with its given precision ?
-isZeroAmount :: Amount -> Bool
-isZeroAmount --  a==missingamt = False
-  = not . any (`elem` digits) . showAmountWithoutPriceOrCommodity
+-- | Does mixed amount appear to be zero when rendered with its
+-- display precision ?
+amountLooksZero :: Amount -> Bool
+amountLooksZero = not . any (`elem` digits) . showAmountWithoutPriceOrCommodity
 
--- | Is this amount "really" zero, regardless of the display precision ?
-isReallyZeroAmount :: Amount -> Bool
-isReallyZeroAmount Amount{aquantity=q} = q == 0
+-- | Is this amount exactly zero, ignoring its display precision ?
+amountIsZero :: Amount -> Bool
+amountIsZero Amount{aquantity=q} = q == 0
 
 -- | Get the string representation of an amount, based on its commodity's
 -- display settings except using the specified precision.
@@ -520,7 +519,7 @@ normaliseHelper squashprices (Mixed as)
     newzero = case filter (/= "") (map acommodity zeros) of
                _:_ -> last zeros
                _   -> nullamt
-    (zeros, nonzeros) = partition isReallyZeroAmount $
+    (zeros, nonzeros) = partition amountIsZero $
                         map sumSimilarAmountsUsingFirstPrice $
                         groupBy groupfn $
                         sortBy sortfn
@@ -619,26 +618,20 @@ isNegativeMixedAmount m =
     as | all isNegativeAmount as -> Just True
     _ -> Nothing  -- multiple amounts with different signs
 
--- XXX rename to mixedAmountLooksZero, mixedAmountIsZero, mixedAmountCostIsZero ?
+-- | Does this mixed amount appear to be zero when rendered with its
+-- display precision ?
+mixedAmountLooksZero :: MixedAmount -> Bool
+mixedAmountLooksZero = all amountLooksZero . amounts . normaliseMixedAmountSquashPricesForDisplay
 
--- | Does this mixed amount appear to be zero when displayed with its given precision ?
-isZeroMixedAmount :: MixedAmount -> Bool
-isZeroMixedAmount = all isZeroAmount . amounts . normaliseMixedAmountSquashPricesForDisplay
-
--- | Is this mixed amount "really" zero ? See isReallyZeroAmount.
-isReallyZeroMixedAmount :: MixedAmount -> Bool
-isReallyZeroMixedAmount = all isReallyZeroAmount . amounts . normaliseMixedAmountSquashPricesForDisplay
-
--- | Is this mixed amount "really" zero, after converting to cost
--- commodities where possible ?
-isReallyZeroMixedAmountCost :: MixedAmount -> Bool
-isReallyZeroMixedAmountCost = isReallyZeroMixedAmount . costOfMixedAmount
+-- | Is this mixed amount exactly zero, ignoring display precisions ?
+mixedAmountIsZero :: MixedAmount -> Bool
+mixedAmountIsZero = all amountIsZero . amounts . normaliseMixedAmountSquashPricesForDisplay
 
 -- -- | MixedAmount derived Eq instance in Types.hs doesn't know that we
 -- -- want $0 = EUR0 = 0. Yet we don't want to drag all this code over there.
 -- -- For now, use this when cross-commodity zero equality is important.
 -- mixedAmountEquals :: MixedAmount -> MixedAmount -> Bool
--- mixedAmountEquals a b = amounts a' == amounts b' || (isZeroMixedAmount a' && isZeroMixedAmount b')
+-- mixedAmountEquals a b = amounts a' == amounts b' || (mixedAmountLooksZero a' && mixedAmountLooksZero b')
 --     where a' = normaliseMixedAmountSquashPricesForDisplay a
 --           b' = normaliseMixedAmountSquashPricesForDisplay b
 
@@ -755,9 +748,9 @@ tests_Amount = tests "Amount" [
        costOfAmount (eur 1){aprice=Just $ TotalPrice $ usd 2} @?= usd 2
        costOfAmount (eur (-1)){aprice=Just $ TotalPrice $ usd 2} @?= usd (-2)
 
-    ,test "isZeroAmount" $ do
-       assertBool "" $ isZeroAmount amount
-       assertBool "" $ isZeroAmount $ usd 0
+    ,test "amountLooksZero" $ do
+       assertBool "" $ amountLooksZero amount
+       assertBool "" $ amountLooksZero $ usd 0
 
     ,test "negating amounts" $ do
        negate (usd 1) @?= (usd 1){aquantity= -1}
@@ -772,7 +765,7 @@ tests_Amount = tests "Amount" [
        asprecision (astyle $ sum [usd 1 `withPrecision` 1, usd 1 `withPrecision` 3]) @?= 3
        asprecision (astyle $ sum [usd 1 `withPrecision` 3, usd 1 `withPrecision` 1]) @?= 3
        -- adding different commodities assumes conversion rate 1
-       assertBool "" $ isZeroAmount (usd 1.23 - eur 1.23)
+       assertBool "" $ amountLooksZero (usd 1.23 - eur 1.23)
 
     ,test "showAmount" $ do
       showAmount (usd 0 + gbp 0) @?= "0"
@@ -825,7 +818,7 @@ tests_Amount = tests "Amount" [
 
     ,test "normaliseMixedAmountSquashPricesForDisplay" $ do
        normaliseMixedAmountSquashPricesForDisplay (Mixed []) @?= Mixed [nullamt]
-       assertBool "" $ isZeroMixedAmount $ normaliseMixedAmountSquashPricesForDisplay
+       assertBool "" $ mixedAmountLooksZero $ normaliseMixedAmountSquashPricesForDisplay
         (Mixed [usd 10
                ,usd 10 @@ eur 7
                ,usd (-10)

hledger-lib/Hledger/Data/Posting.hs

@@ -253,7 +253,7 @@ isPostingInDateSpan' PrimaryDate   s = spanContainsDate s . postingDate
 isPostingInDateSpan' SecondaryDate s = spanContainsDate s . postingDate2
 
 isEmptyPosting :: Posting -> Bool
-isEmptyPosting = isZeroMixedAmount . pamount
+isEmptyPosting = mixedAmountLooksZero . pamount
 
 -- AccountName stuff that depends on PostingType
 

hledger-lib/Hledger/Data/Transaction.hs

@@ -357,7 +357,7 @@ transactionCheckBalanced mstyles t = errs
     -- check for mixed signs, detecting nonzeros at display precision
     canonicalise = maybe id canonicaliseMixedAmount mstyles
     signsOk ps = 
-      case filter (not.isZeroMixedAmount) $ map (canonicalise.costOfMixedAmount.pamount) ps of
+      case filter (not.mixedAmountLooksZero) $ map (canonicalise.costOfMixedAmount.pamount) ps of
         nonzeros | length nonzeros >= 2
                    -> length (nubSort $ mapMaybe isNegativeMixedAmount nonzeros) > 1
         _          -> True
@@ -367,7 +367,7 @@ transactionCheckBalanced mstyles t = errs
     (rsum, bvsum)               = (sumPostings rps, sumPostings bvps)
     (rsumcost, bvsumcost)       = (costOfMixedAmount rsum, costOfMixedAmount bvsum)
     (rsumdisplay, bvsumdisplay) = (canonicalise rsumcost, canonicalise bvsumcost)
-    (rsumok, bvsumok)           = (isZeroMixedAmount rsumdisplay, isZeroMixedAmount bvsumdisplay)
+    (rsumok, bvsumok)           = (mixedAmountLooksZero rsumdisplay, mixedAmountLooksZero bvsumdisplay)
 
     -- generate error messages, showing amounts with their original precision
     errs = filter (not.null) [rmsg, bvmsg]

hledger-lib/Hledger/Query.hs

@@ -606,9 +606,9 @@ matchesPosting (Real v) p = v == isReal p
 matchesPosting q@(Depth _) Posting{paccount=a} = q `matchesAccount` a
 matchesPosting q@(Amt _ _) Posting{pamount=amt} = q `matchesMixedAmount` amt
 -- matchesPosting q@(Amt _ _) Posting{pamount=amt} = q `matchesMixedAmount` amt
--- matchesPosting (Empty v) Posting{pamount=a} = v == isZeroMixedAmount a
+-- matchesPosting (Empty v) Posting{pamount=a} = v == mixedAmountLooksZero a
 -- matchesPosting (Empty False) Posting{pamount=a} = True
--- matchesPosting (Empty True) Posting{pamount=a} = isZeroMixedAmount a
+-- matchesPosting (Empty True) Posting{pamount=a} = mixedAmountLooksZero a
 matchesPosting (Empty _) _ = True
 matchesPosting (Sym r) Posting{pamount=Mixed as} = any (matchesCommodity (Sym r)) $ map acommodity as
 matchesPosting (Tag n v) p = case (n, v) of

hledger-lib/Hledger/Read/CsvReader.hs

@@ -898,7 +898,7 @@ getAmount rules record currency p1IsVirtual n =
     assignments''
       | length assignments' > 1 && not (null nonzeros) = nonzeros
       | otherwise                                      = assignments'
-      where nonzeros = filter (not . isZeroMixedAmount . snd) assignments'
+      where nonzeros = filter (not . mixedAmountLooksZero . snd) assignments'
 
   in case -- dbg0 ("amounts for posting "++show n)
           assignments'' of

hledger-lib/Hledger/Reports/BalanceReport.hs

@@ -110,9 +110,9 @@ balanceReport ropts@ReportOpts{..} q j =
                          clipAccounts (queryDepth q) valuedaccttree
           where
             balance     = if flat_ ropts then aebalance else aibalance
-            filterzeros = if empty_ then id else filter (not . isZeroMixedAmount . balance)
-            filterempty = filter (\a -> anumpostings a > 0 || not (isZeroMixedAmount (balance a)))
-            prunezeros  = if empty_ then id else fromMaybe nullacct . pruneAccounts (isZeroMixedAmount . balance)
+            filterzeros = if empty_ then id else filter (not . mixedAmountLooksZero . balance)
+            filterempty = filter (\a -> anumpostings a > 0 || not (mixedAmountLooksZero (balance a)))
+            prunezeros  = if empty_ then id else fromMaybe nullacct . pruneAccounts (mixedAmountLooksZero . balance)
             markboring  = if no_elide_ then id else markBoringParentAccounts
 
       -- Make a report row for each account.
@@ -165,7 +165,7 @@ sortAccountItemsLike sortedas items =
 markBoringParentAccounts :: Account -> Account
 markBoringParentAccounts = tieAccountParents . mapAccounts mark
   where
-    mark a | length (asubs a) == 1 && isZeroMixedAmount (aebalance a) = a{aboring=True}
+    mark a | length (asubs a) == 1 && mixedAmountLooksZero (aebalance a) = a{aboring=True}
            | otherwise = a
 
 balanceReportItem :: ReportOpts -> Query -> Account -> BalanceReportItem
@@ -204,9 +204,9 @@ unifyMixedAmount :: MixedAmount -> Amount
 unifyMixedAmount mixedAmount = foldl combine (num 0) (amounts mixedAmount)
   where
     combine amount result =
-      if isReallyZeroAmount amount
+      if amountIsZero amount
       then result
-      else if isReallyZeroAmount result
+      else if amountIsZero result
         then amount
         else if acommodity amount == acommodity result
           then amount + result
@@ -218,7 +218,7 @@ perdivide :: MixedAmount -> MixedAmount -> MixedAmount
 perdivide a b =
   let a' = unifyMixedAmount a
       b' = unifyMixedAmount b
-  in if isReallyZeroAmount a' || isReallyZeroAmount b' || acommodity a' == acommodity b'
+  in if amountIsZero a' || amountIsZero b' || acommodity a' == acommodity b'
     then mixed [per $ if aquantity b' == 0 then 0 else (aquantity a' / abs (aquantity b') * 100)]
     else error' "Cannot calculate percentages if accounts have different commodities. (Hint: Try --cost, -V or similar flags.)"
 

hledger-lib/Hledger/Reports/BudgetReport.hs

@@ -291,7 +291,7 @@ budgetReportAsText ropts@ReportOpts{..} budgetr =
     percentage :: Change -> BudgetGoal -> Maybe Percentage
     percentage actual budget =
       case (maybecost $ normaliseMixedAmount actual, maybecost $ normaliseMixedAmount budget) of
-        (Mixed [a], Mixed [b]) | (acommodity a == acommodity b || isZeroAmount a) && not (isZeroAmount b)
+        (Mixed [a], Mixed [b]) | (acommodity a == acommodity b || amountLooksZero a) && not (amountLooksZero b)
             -> Just $ 100 * aquantity a / aquantity b
         _   -> -- trace (pshow $ (maybecost actual, maybecost budget))  -- debug missing percentage
                Nothing

hledger-lib/Hledger/Reports/MultiBalanceReport.hs

@@ -249,7 +249,7 @@ multiBalanceReportWith ropts@ReportOpts{..} q j priceoracle =
              -- Total for a cumulative/historical report is always zero.
            , let rowtot = if balancetype_==PeriodChange then sum valuedrowbals else 0
            , let rowavg = averageMixedAmounts valuedrowbals
-           , empty_ || depth == 0 || any (not . isZeroMixedAmount) valuedrowbals
+           , empty_ || depth == 0 || any (not . mixedAmountLooksZero) valuedrowbals
            ]
         where
           avalue periodlast =

hledger-lib/Hledger/Reports/PostingsReport.hs

@@ -253,7 +253,7 @@ summarisePostingsInDateSpan (DateSpan b e) wd depth showempty ps
                     | otherwise = ["..."]
       summaryps | depth > 0 = [summaryp{paccount=a,pamount=balance a} | a <- clippedanames]
                 | otherwise = [summaryp{paccount="...",pamount=sum $ map pamount ps}]
-      summarypes = map (, e') $ (if showempty then id else filter (not . isZeroMixedAmount . pamount)) summaryps
+      summarypes = map (, e') $ (if showempty then id else filter (not . mixedAmountLooksZero . pamount)) summaryps
       anames = nubSort $ map paccount ps
       -- aggregate balances by account, like ledgerFromJournal, then do depth-clipping
       accts = accountsFromPostings ps

hledger-ui/Hledger/UI/RegisterScreen.hs

@@ -80,7 +80,7 @@ rsInit d reset ui@UIState{aopts=_uopts@UIOpts{cliopts_=CliOpts{reportopts_=ropts
           ]
 
     (_label,items) = accountTransactionsReport ropts' j q thisacctq
-    items' = (if empty_ ropts' then id else filter (not . isZeroMixedAmount . fifth6)) $  -- without --empty, exclude no-change txns
+    items' = (if empty_ ropts' then id else filter (not . mixedAmountLooksZero . fifth6)) $  -- without --empty, exclude no-change txns
              reverse  -- most recent last
              items
 

hledger/Hledger/Cli/Commands/Add.hs

@@ -339,7 +339,7 @@ amountAndCommentWizard PrevInput{..} EntryState{..} = do
       def = case (esArgs, mhistoricalp, followedhistoricalsofar) of
               (d:_,_,_)                                             -> d
               (_,Just hp,True)                                      -> showamt $ pamount hp
-              _  | pnum > 1 && not (isZeroMixedAmount balancingamt) -> showamt balancingamtfirstcommodity
+              _  | pnum > 1 && not (mixedAmountLooksZero balancingamt) -> showamt balancingamtfirstcommodity
               _                                                     -> ""
   retryMsg "A valid hledger amount is required. Eg: 1, $2, 3 EUR, \"4 red apples\"." $
    parser parseAmountAndComment $

hledger/Hledger/Cli/CompoundBalanceCommand.hs

@@ -274,11 +274,11 @@ compoundBalanceSubreport ropts@ReportOpts{..} userq j priceoracle subreportqfn s
             nonzeroaccounts =
               dbg1 "nonzeroaccounts" $
               mapMaybe (\(PeriodicReportRow act _ amts _ _) ->
-                            if not (all isZeroMixedAmount amts) then Just act else Nothing) rows
+                            if not (all mixedAmountLooksZero amts) then Just act else Nothing) rows
             rows' = filter (not . emptyRow) rows
               where
                 emptyRow (PeriodicReportRow act _ amts _ _) =
-                  all isZeroMixedAmount amts && not (any (act `isAccountNamePrefixOf`) nonzeroaccounts)
+                  all mixedAmountLooksZero amts && not (any (act `isAccountNamePrefixOf`) nonzeroaccounts)
 
 -- | Render a compound balance report as plain text suitable for console output.
 {- Eg: