hledger/hledger-lib/Hledger/Data/Amount.hs
2012-01-01 00:39:13 +00:00

472 lines
19 KiB
Haskell

{-# LANGUAGE StandaloneDeriving #-}
{-|
A simple 'Amount' is some quantity of money, shares, or anything else.
It has a (possibly null) 'Commodity' and a numeric quantity:
@
$1
£-50
EUR 3.44
GOOG 500
1.5h
90 apples
0
@
It may also have an assigned 'Price', representing this amount's per-unit
or total cost in a different commodity. If present, this is rendered like
so:
@
EUR 2 \@ $1.50 (unit price)
EUR 2 \@\@ $3 (total price)
@
A 'MixedAmount' is zero or more simple amounts, so can represent multiple
commodities; this is the type most often used:
@
0
$50 + EUR 3
16h + $13.55 + AAPL 500 + 6 oranges
@
When a mixed amount has been \"normalised\", it has no more than one amount
in each commodity and no zero amounts; or it has just a single zero amount
and no others.
Limited arithmetic with simple and mixed amounts is supported, best used
with similar amounts since it mostly ignores assigned prices and commodity
exchange rates.
-}
module Hledger.Data.Amount (
-- * Amount
nullamt,
amountWithCommodity,
canonicaliseAmountCommodity,
setAmountPrecision,
-- ** arithmetic
costOfAmount,
divideAmount,
-- ** rendering
showAmount,
showAmountDebug,
showAmountWithoutPrice,
maxprecision,
maxprecisionwithpoint,
-- * MixedAmount
nullmixedamt,
missingamt,
amounts,
normaliseMixedAmountPreservingFirstPrice,
canonicaliseMixedAmountCommodity,
mixedAmountWithCommodity,
setMixedAmountPrecision,
-- ** arithmetic
costOfMixedAmount,
divideMixedAmount,
isNegativeMixedAmount,
isZeroMixedAmount,
isReallyZeroMixedAmountCost,
-- ** rendering
showMixedAmount,
showMixedAmountDebug,
showMixedAmountWithoutPrice,
showMixedAmountWithPrecision,
-- * misc.
tests_Hledger_Data_Amount
) where
import Data.Char (isDigit)
import Data.List
import Data.Map (findWithDefault)
import Test.HUnit
import Text.Printf
import qualified Data.Map as Map
import Hledger.Data.Types
import Hledger.Data.Commodity
import Hledger.Utils
deriving instance Show HistoricalPrice
-------------------------------------------------------------------------------
-- Amount
instance Show Amount where show = showAmount
instance Num Amount where
abs (Amount c q p) = Amount c (abs q) p
signum (Amount c q p) = Amount c (signum q) p
fromInteger i = Amount (comm "") (fromInteger i) Nothing
negate a@Amount{quantity=q} = a{quantity=(-q)}
(+) = similarAmountsOp (+)
(-) = similarAmountsOp (-)
(*) = similarAmountsOp (*)
-- | The empty simple amount.
nullamt :: Amount
nullamt = Amount unknown 0 Nothing
-- | Apply a binary arithmetic operator to two amounts, ignoring and
-- discarding any assigned prices, and converting the first to the
-- commodity of the second in a simplistic way (1-1 exchange rate).
-- The highest precision of either amount is preserved in the result.
similarAmountsOp :: (Double -> Double -> Double) -> Amount -> Amount -> Amount
similarAmountsOp op a@(Amount Commodity{precision=ap} _ _) (Amount bc@Commodity{precision=bp} bq _) =
Amount bc{precision=max ap bp} (quantity (amountWithCommodity bc a) `op` bq) Nothing
-- | Convert an amount to the specified commodity, ignoring and discarding
-- any assigned prices and assuming an exchange rate of 1.
amountWithCommodity :: Commodity -> Amount -> Amount
amountWithCommodity c (Amount _ q _) = Amount c q Nothing
-- | Convert an amount to the commodity of its assigned price, if any. Notes:
--
-- - price amounts must be MixedAmounts with exactly one component Amount (or there will be a runtime error)
--
-- - price amounts should be positive, though this is not currently enforced
costOfAmount :: Amount -> Amount
costOfAmount a@(Amount _ q price) =
case price of
Nothing -> a
Just (UnitPrice (Mixed [Amount pc pq Nothing])) -> Amount pc (pq*q) Nothing
Just (TotalPrice (Mixed [Amount pc pq Nothing])) -> Amount pc (pq*signum q) Nothing
_ -> error' "costOfAmount: Malformed price encountered, programmer error"
-- | Divide an amount's quantity by a constant.
divideAmount :: Amount -> Double -> Amount
divideAmount a@Amount{quantity=q} d = a{quantity=q/d}
-- | Is this amount negative ? The price is ignored.
isNegativeAmount :: Amount -> Bool
isNegativeAmount Amount{quantity=q} = q < 0
-- | Does this amount appear to be zero when displayed with its given precision ?
isZeroAmount :: Amount -> Bool
isZeroAmount = null . filter (`elem` "123456789") . showAmountWithoutPriceOrCommodity
-- | Is this amount "really" zero, regardless of the display precision ?
-- Since we are using floating point, for now just test to some high precision.
isReallyZeroAmount :: Amount -> Bool
isReallyZeroAmount = null . filter (`elem` "123456789") . printf ("%."++show zeroprecision++"f") . quantity
where zeroprecision = 8
-- | Get the string representation of an amount, based on its commodity's
-- display settings except using the specified precision.
showAmountWithPrecision :: Int -> Amount -> String
showAmountWithPrecision p = showAmount . setAmountPrecision p
-- | Set the display precision in the amount's commodity.
setAmountPrecision :: Int -> Amount -> Amount
setAmountPrecision p a@Amount{commodity=c} = a{commodity=c{precision=p}}
-- | Get the unambiguous string representation of an amount, for debugging.
showAmountDebug :: Amount -> String
showAmountDebug (Amount c q pri) = printf "Amount {commodity = %s, quantity = %s, price = %s}"
(show c) (show q) (maybe "" showPriceDebug pri)
-- | Get the string representation of an amount, without any \@ price.
showAmountWithoutPrice :: Amount -> String
showAmountWithoutPrice a = showAmount a{price=Nothing}
-- | Get the string representation of an amount, without any price or commodity symbol.
showAmountWithoutPriceOrCommodity :: Amount -> String
showAmountWithoutPriceOrCommodity a@Amount{commodity=c} = showAmount a{commodity=c{symbol=""}, price=Nothing}
showPrice :: Price -> String
showPrice (UnitPrice pa) = " @ " ++ showMixedAmount pa
showPrice (TotalPrice pa) = " @@ " ++ showMixedAmount pa
showPriceDebug :: Price -> String
showPriceDebug (UnitPrice pa) = " @ " ++ showMixedAmountDebug pa
showPriceDebug (TotalPrice pa) = " @@ " ++ showMixedAmountDebug pa
-- | Get the string representation of an amount, based on its commodity's
-- display settings. String representations equivalent to zero are
-- converted to just \"0\".
showAmount :: Amount -> String
showAmount (Amount (Commodity {symbol="AUTO"}) _ _) = "" -- can appear in an error message
showAmount a@(Amount (Commodity {symbol=sym,side=side,spaced=spaced}) _ pri) =
case side of
L -> printf "%s%s%s%s" sym' space quantity' price
R -> printf "%s%s%s%s" quantity' space sym' price
where
quantity = showamountquantity a
displayingzero = null $ filter (`elem` "123456789") $ quantity
(quantity',sym') | displayingzero = ("0","")
| otherwise = (quantity,quoteCommoditySymbolIfNeeded sym)
space = if (not (null sym') && spaced) then " " else ""
price = maybe "" showPrice pri
-- | Get the string representation of the number part of of an amount,
-- using the display settings from its commodity.
showamountquantity :: Amount -> String
showamountquantity (Amount (Commodity {decimalpoint=d,precision=p,separator=s,separatorpositions=spos}) q _) =
punctuatenumber d s spos $ qstr
where
-- isint n = fromIntegral (round n) == n
qstr -- p == maxprecision && isint q = printf "%d" (round q::Integer)
| p == maxprecisionwithpoint = printf "%f" q
| p == maxprecision = chopdotzero $ printf "%f" q
| otherwise = printf ("%."++show p++"f") q
-- | Replace a number string's decimal point with the specified character,
-- and add the specified digit group separators.
punctuatenumber :: Char -> Char -> [Int] -> String -> String
punctuatenumber dec sep grps str = sign ++ reverse (addseps sep (extend grps) (reverse int)) ++ frac''
where
(sign,num) = break isDigit str
(int,frac) = break (=='.') num
frac' = dropWhile (=='.') frac
frac'' | null frac' = ""
| otherwise = dec:frac'
extend [] = []
extend gs = init gs ++ repeat (last gs)
addseps _ [] str = str
addseps sep (g:gs) str
| length str <= g = str
| otherwise = let (s,rest) = splitAt g str
in s ++ [sep] ++ addseps sep gs rest
chopdotzero str = reverse $ case reverse str of
'0':'.':s -> s
s -> s
-- | For rendering: a special precision value which means show all available digits.
maxprecision :: Int
maxprecision = 999998
-- | For rendering: a special precision value which forces display of a decimal point.
maxprecisionwithpoint :: Int
maxprecisionwithpoint = 999999
-- | Replace an amount's commodity with the canonicalised version from
-- the provided commodity map.
canonicaliseAmountCommodity :: Maybe (Map.Map String Commodity) -> Amount -> Amount
canonicaliseAmountCommodity Nothing = id
canonicaliseAmountCommodity (Just canonicalcommoditymap) = fixamount
where
-- like journalCanonicaliseAmounts
fixamount a@Amount{commodity=c} = a{commodity=fixcommodity c}
fixcommodity c@Commodity{symbol=s} = findWithDefault c s canonicalcommoditymap
-------------------------------------------------------------------------------
-- MixedAmount
instance Show MixedAmount where show = showMixedAmount
instance Num MixedAmount where
fromInteger i = Mixed [Amount (comm "") (fromInteger i) Nothing]
negate (Mixed as) = Mixed $ map negate as
(+) (Mixed as) (Mixed bs) = normaliseMixedAmountPreservingPrices $ Mixed $ as ++ bs
(*) = error' "programming error, mixed amounts do not support multiplication"
abs = error' "programming error, mixed amounts do not support abs"
signum = error' "programming error, mixed amounts do not support signum"
-- | The empty mixed amount.
nullmixedamt :: MixedAmount
nullmixedamt = Mixed []
-- | A temporary value for parsed transactions which had no amount specified.
missingamt :: MixedAmount
missingamt = Mixed [Amount unknown{symbol="AUTO"} 0 Nothing]
-- | Simplify a mixed amount's component amounts: combine amounts with
-- the same commodity and price. Also remove any zero amounts and
-- replace an empty amount list with a single zero amount.
normaliseMixedAmountPreservingPrices :: MixedAmount -> MixedAmount
normaliseMixedAmountPreservingPrices (Mixed as) = Mixed as''
where
as'' = if null nonzeros then [nullamt] else nonzeros
(_,nonzeros) = partition (\a -> isReallyZeroAmount a && Mixed [a] /= missingamt) as'
as' = map sumAmountsUsingFirstPrice $ group $ sort as
sort = sortBy (\a1 a2 -> compare (sym a1,price a1) (sym a2,price a2))
group = groupBy (\a1 a2 -> sym a1 == sym a2 && price a1 == price a2)
sym = symbol . commodity
-- | Simplify a mixed amount's component amounts: combine amounts with
-- the same commodity, using the first amount's price for subsequent
-- amounts in each commodity (ie, this function alters the amount and
-- is best used as a rendering helper.). Also remove any zero amounts
-- and replace an empty amount list with a single zero amount.
normaliseMixedAmountPreservingFirstPrice :: MixedAmount -> MixedAmount
normaliseMixedAmountPreservingFirstPrice (Mixed as) = Mixed as''
where
as'' = if null nonzeros then [nullamt] else nonzeros
(_,nonzeros) = partition (\a -> isReallyZeroAmount a && Mixed [a] /= missingamt) as'
as' = map sumAmountsUsingFirstPrice $ group $ sort as
sort = sortBy (\a1 a2 -> compare (sym a1) (sym a2))
group = groupBy (\a1 a2 -> sym a1 == sym a2)
sym = symbol . commodity
-- discardPrice :: Amount -> Amount
-- discardPrice a = a{price=Nothing}
-- discardPrices :: MixedAmount -> MixedAmount
-- discardPrices (Mixed as) = Mixed $ map discardPrice as
sumAmountsUsingFirstPrice [] = nullamt
sumAmountsUsingFirstPrice as = (sum as){price=price $ head as}
-- | Get a mixed amount's component amounts.
amounts :: MixedAmount -> [Amount]
amounts (Mixed as) = 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 -> Double -> MixedAmount
divideMixedAmount (Mixed as) d = Mixed $ map (flip divideAmount d) as
-- | Is this mixed amount negative, if it can be normalised to a single commodity ?
isNegativeMixedAmount :: MixedAmount -> Maybe Bool
isNegativeMixedAmount m = case as of [a] -> Just $ isNegativeAmount a
_ -> Nothing
where as = amounts $ normaliseMixedAmountPreservingFirstPrice m
-- | Does this mixed amount appear to be zero when displayed with its given precision ?
isZeroMixedAmount :: MixedAmount -> Bool
isZeroMixedAmount = all isZeroAmount . amounts . normaliseMixedAmountPreservingFirstPrice
-- | Is this mixed amount "really" zero ? See isReallyZeroAmount.
isReallyZeroMixedAmount :: MixedAmount -> Bool
isReallyZeroMixedAmount = all isReallyZeroAmount . amounts . normaliseMixedAmountPreservingFirstPrice
-- | Is this mixed amount "really" zero, after converting to cost
-- commodities where possible ?
isReallyZeroMixedAmountCost :: MixedAmount -> Bool
isReallyZeroMixedAmountCost = isReallyZeroMixedAmount . costOfMixedAmount
-- -- | Convert a mixed amount to the specified commodity, assuming an exchange rate of 1.
mixedAmountWithCommodity :: Commodity -> MixedAmount -> Amount
mixedAmountWithCommodity c (Mixed as) = Amount c total Nothing
where
total = sum $ map (quantity . amountWithCommodity c) as
-- -- | 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')
-- where a' = normaliseMixedAmountPreservingFirstPrice a
-- b' = normaliseMixedAmountPreservingFirstPrice b
-- | Get the string representation of a mixed amount, showing each of
-- its component amounts. NB a mixed amount can have an empty amounts
-- list in which case it shows as \"\".
showMixedAmount :: MixedAmount -> String
showMixedAmount m = vConcatRightAligned $ map show $ amounts $ normaliseMixedAmountPreservingFirstPrice m
-- | Set the display precision in the amount's commodities.
setMixedAmountPrecision :: Int -> MixedAmount -> MixedAmount
setMixedAmountPrecision p (Mixed as) = Mixed $ map (setAmountPrecision p) as
-- | Get the string representation of a mixed amount, showing each of its
-- component amounts with the specified precision, ignoring their
-- commoditys' display precision settings.
showMixedAmountWithPrecision :: Int -> MixedAmount -> String
showMixedAmountWithPrecision p m =
vConcatRightAligned $ map (showAmountWithPrecision p) $ amounts $ normaliseMixedAmountPreservingFirstPrice m
-- | Get an unambiguous string representation of a mixed amount for debugging.
showMixedAmountDebug :: MixedAmount -> String
showMixedAmountDebug m = printf "Mixed [%s]" as
where as = intercalate "\n " $ map showAmountDebug $ amounts $ normaliseMixedAmountPreservingFirstPrice m
-- | Get the string representation of a mixed amount, but without
-- any \@ prices.
showMixedAmountWithoutPrice :: MixedAmount -> String
showMixedAmountWithoutPrice m = concat $ intersperse "\n" $ map showfixedwidth as
where
(Mixed as) = normaliseMixedAmountPreservingFirstPrice $ stripPrices m
stripPrices (Mixed as) = Mixed $ map stripprice as where stripprice a = a{price=Nothing}
width = maximum $ map (length . show) as
showfixedwidth = printf (printf "%%%ds" width) . showAmountWithoutPrice
-- | Replace a mixed amount's commodity with the canonicalised version from
-- the provided commodity map.
canonicaliseMixedAmountCommodity :: Maybe (Map.Map String Commodity) -> MixedAmount -> MixedAmount
canonicaliseMixedAmountCommodity canonicalcommoditymap (Mixed as) = Mixed $ map (canonicaliseAmountCommodity canonicalcommoditymap) as
-------------------------------------------------------------------------------
-- misc
tests_Hledger_Data_Amount = TestList [
-- Amount
"costOfAmount" ~: do
costOfAmount (euros 1) `is` euros 1
costOfAmount (euros 2){price=Just $ UnitPrice $ Mixed [dollars 2]} `is` dollars 4
costOfAmount (euros 1){price=Just $ TotalPrice $ Mixed [dollars 2]} `is` dollars 2
costOfAmount (euros (-1)){price=Just $ TotalPrice $ Mixed [dollars 2]} `is` dollars (-2)
,"isZeroAmount" ~: do
assertBool "" $ isZeroAmount $ Amount unknown 0 Nothing
assertBool "" $ isZeroAmount $ dollars 0
,"negating amounts" ~: do
let a = dollars 1
negate a `is` a{quantity=(-1)}
let b = (dollars 1){price=Just $ UnitPrice $ Mixed [euros 2]}
negate b `is` b{quantity=(-1)}
,"adding amounts" ~: do
let a1 = dollars 1.23
let a2 = dollars (-1.23)
let a3 = dollars (-1.23)
(a1 + a2) `is` Amount (comm "$") 0 Nothing
(a1 + a3) `is` Amount (comm "$") 0 Nothing
(a2 + a3) `is` Amount (comm "$") (-2.46) Nothing
(a3 + a3) `is` Amount (comm "$") (-2.46) Nothing
sum [a1,a2,a3,-a3] `is` Amount (comm "$") 0 Nothing
-- highest precision is preserved
let ap1 = (dollars 1){commodity=dollar{precision=1}}
ap3 = (dollars 1){commodity=dollar{precision=3}}
(sum [ap1,ap3]) `is` ap3{quantity=2}
(sum [ap3,ap1]) `is` ap3{quantity=2}
-- adding different commodities assumes conversion rate 1
assertBool "" $ isZeroAmount (a1 - euros 1.23)
,"showAmount" ~: do
showAmount (dollars 0 + pounds 0) `is` "0"
-- MixedAmount
,"normaliseMixedAmountPreservingFirstPrice" ~: do
normaliseMixedAmountPreservingFirstPrice (Mixed []) `is` Mixed [nullamt]
assertBool "" $ isZeroMixedAmount $ normaliseMixedAmountPreservingFirstPrice (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}]))}
])
,"adding mixed amounts" ~: do
let dollar0 = dollar{precision=0}
(sum $ map (Mixed . (\a -> [a]))
[Amount dollar 1.25 Nothing,
Amount dollar0 (-1) Nothing,
Amount dollar (-0.25) Nothing])
`is` Mixed [Amount unknown 0 Nothing]
,"showMixedAmount" ~: do
showMixedAmount (Mixed [dollars 1]) `is` "$1.00"
showMixedAmount (Mixed [(dollars 1){price=Just $ UnitPrice $ Mixed [euros 2]}]) `is` "$1.00 @ €2.00"
showMixedAmount (Mixed [dollars 0]) `is` "0"
showMixedAmount (Mixed []) `is` "0"
showMixedAmount missingamt `is` ""
,"showMixedAmountWithoutPrice" ~: do
let a = (dollars 1){price=Just $ UnitPrice $ Mixed [euros 2]}
showMixedAmountWithoutPrice (Mixed [a]) `is` "$1.00"
showMixedAmountWithoutPrice (Mixed [a, (-a)]) `is` "0"
]