pwncash/lib/Internal/Types.hs

764 lines
21 KiB
Haskell

{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE UndecidableInstances #-}
module Internal.Types where
import Data.Fix (Fix (..), foldFix)
import Data.Functor.Foldable (embed)
import qualified Data.Functor.Foldable.TH as TH
import Database.Persist.Sql hiding (Desc, In, Statement)
import Database.Persist.TH
import Dhall hiding (embed, maybe)
import Dhall.TH
import Internal.TH (deriveProduct)
import Language.Haskell.TH.Syntax (Lift)
import RIO
import qualified RIO.Map as M
import qualified RIO.NonEmpty as NE
import qualified RIO.Text as T
import RIO.Time
import Text.Regex.TDFA
-------------------------------------------------------------------------------
-- DHALL CONFIG
-------------------------------------------------------------------------------
makeHaskellTypesWith
(defaultGenerateOptions {generateToDhallInstance = False, generateFromDhallInstance = False})
[ MultipleConstructors "SqlConfig" "(./dhall/Types.dhall).SqlConfig"
, MultipleConstructors "TimeUnit" "(./dhall/Types.dhall).TimeUnit"
, MultipleConstructors "Weekday" "(./dhall/Types.dhall).Weekday"
, MultipleConstructors "WeekdayPat" "(./dhall/Types.dhall).WeekdayPat"
, MultipleConstructors "MDYPat" "(./dhall/Types.dhall).MDYPat"
, MultipleConstructors "DatePat" "(./dhall/Types.dhall).DatePat"
, MultipleConstructors "YMDMatcher" "(./dhall/Types.dhall).YMDMatcher"
, MultipleConstructors "DateMatcher" "(./dhall/Types.dhall).DateMatcher"
, MultipleConstructors "EntryNumGetter" "(./dhall/Types.dhall).EntryNumGetter"
, MultipleConstructors "BudgetCurrency" "(./dhall/Types.dhall).BudgetCurrency"
, MultipleConstructors "BudgetTransferType" "(./dhall/Types.dhall).BudgetTransferType"
, MultipleConstructors "TaxMethod" "(./dhall/Types.dhall).TaxMethod"
, SingleConstructor "Currency" "Currency" "(./dhall/Types.dhall).Currency"
, SingleConstructor "Tag" "Tag" "(./dhall/Types.dhall).Tag"
, SingleConstructor "TaggedAcnt" "TaggedAcnt" "(./dhall/Types.dhall).TaggedAcnt"
, SingleConstructor "Gregorian" "Gregorian" "(./dhall/Types.dhall).Gregorian"
, SingleConstructor "GregorianM" "GregorianM" "(./dhall/Types.dhall).GregorianM"
, SingleConstructor "Interval" "Interval" "(./dhall/Types.dhall).Interval"
, SingleConstructor "TemporalScope" "TemporalScope" "(./dhall/Types.dhall).TemporalScope"
, SingleConstructor "RepeatPat" "RepeatPat" "(./dhall/Types.dhall).RepeatPat"
, SingleConstructor "ModPat" "ModPat" "(./dhall/Types.dhall).ModPat.Type"
, SingleConstructor "CronPat" "CronPat" "(./dhall/Types.dhall).CronPat.Type"
, SingleConstructor "Decimal" "D" "(./dhall/Types.dhall).Decimal"
, SingleConstructor "ValMatcher" "ValMatcher" "(./dhall/Types.dhall).ValMatcher.Type"
, SingleConstructor "Amount" "Amount" "(./dhall/Types.dhall).Amount"
, SingleConstructor "AcntSet" "AcntSet" "(./dhall/Types.dhall).AcntSet.Type"
, SingleConstructor "TransferMatcher" "TransferMatcher" "(./dhall/Types.dhall).TransferMatcher.Type"
, SingleConstructor "ShadowTransfer" "ShadowTransfer" "(./dhall/Types.dhall).ShadowTransfer"
, -- , SingleConstructor "Income" "Income" "(./dhall/Types.dhall).Income.Type"
SingleConstructor "Exchange" "Exchange" "(./dhall/Types.dhall).Exchange"
, SingleConstructor "Field" "Field" "(./dhall/Types.dhall).Field"
, SingleConstructor "Entry" "Entry" "(./dhall/Types.dhall).Entry"
, SingleConstructor "PretaxValue" "PretaxValue" "(./dhall/Types.dhall).PretaxValue"
, SingleConstructor "TaxBracket" "TaxBracket" "(./dhall/Types.dhall).TaxBracket"
, SingleConstructor "TaxProgression" "TaxProgression" "(./dhall/Types.dhall).TaxProgression"
, SingleConstructor "TaxValue" "TaxValue" "(./dhall/Types.dhall).TaxValue"
, SingleConstructor "PosttaxValue" "PosttaxValue" "(./dhall/Types.dhall).PosttaxValue"
, SingleConstructor "BudgetTransferValue" "BudgetTransferValue" "(./dhall/Types.dhall).BudgetTransferValue"
-- , SingleConstructor "ToTx" "ToTx" "(./dhall/Types.dhall).ToTx"
-- , SingleConstructor "FieldMatcher" "FieldMatcher" "(./dhall/Types.dhall).FieldMatcher_"
-- , SingleConstructor "Match" "Match" "(./dhall/Types.dhall).Match_"
-- , SingleConstructor "Budget" "Budget" "(./dhall/Types.dhall).Budget"
-- SingleConstructor "Transfer" "Transfer" "(./dhall/Types.dhall).Transfer"
]
deriveProduct
["Eq", "Show", "Generic", "FromDhall"]
[ "Currency"
, "Tag"
, "TimeUnit"
, "Weekday"
, "WeekdayPat"
, "RepeatPat"
, "MDYPat"
, "Gregorian"
, "GregorianM"
, "Interval"
, "ModPat"
, "CronPat"
, "DatePat"
, "TaggedAcnt"
, "Budget"
, "Income"
, "ShadowTransfer"
, "TransferMatcher"
, "AcntSet"
, "DateMatcher"
, "ValMatcher"
, "YMDMatcher"
, "Decimal"
, "BudgetCurrency"
, "Exchange"
, "EntryNumGetter"
, "TemporalScope"
, "SqlConfig"
, "PretaxValue"
, "TaxValue"
, "TaxBracket"
, "TaxProgression"
, "TaxMethod"
, "PosttaxValue"
, "BudgetTransferValue"
, "BudgetTransferType"
]
-------------------------------------------------------------------------------
-- lots of instances for dhall types
deriving instance Lift Currency
deriving instance Hashable Currency
deriving instance Lift Tag
deriving instance Hashable Tag
deriving instance Ord TimeUnit
deriving instance Hashable TimeUnit
deriving instance Ord Weekday
deriving instance Hashable Weekday
deriving instance Enum Weekday
deriving instance Ord WeekdayPat
deriving instance Hashable WeekdayPat
deriving instance Ord RepeatPat
deriving instance Hashable RepeatPat
deriving instance Ord MDYPat
deriving instance Hashable MDYPat
deriving instance Hashable Gregorian
deriving instance Hashable GregorianM
-- Dhall.TH rearranges my fields :(
instance Ord Gregorian where
compare
Gregorian {gYear = y, gMonth = m, gDay = d}
Gregorian {gYear = y', gMonth = m', gDay = d'} =
compare y y'
<> compare m m'
<> compare d d'
instance Ord GregorianM where
compare
GregorianM {gmYear = y, gmMonth = m}
GregorianM {gmYear = y', gmMonth = m'} = compare y y' <> compare m m'
deriving instance Hashable Interval
deriving instance Ord ModPat
deriving instance Hashable ModPat
deriving instance Ord CronPat
deriving instance Hashable CronPat
deriving instance Ord DatePat
deriving instance Hashable DatePat
type BudgetTransfer =
Transfer TaggedAcnt BudgetCurrency DatePat BudgetTransferValue
data Budget = Budget
{ bgtLabel :: Text
, bgtIncomes :: [Income]
, bgtPretax :: [MultiAllocation PretaxValue]
, bgtTax :: [MultiAllocation TaxValue]
, bgtPosttax :: [MultiAllocation PosttaxValue]
, bgtTransfers :: [BudgetTransfer]
, bgtShadowTransfers :: [ShadowTransfer]
}
deriving instance Hashable PretaxValue
deriving instance Hashable TaxBracket
deriving instance Hashable TaxProgression
deriving instance Hashable TaxMethod
deriving instance Hashable TaxValue
deriving instance Hashable PosttaxValue
deriving instance Hashable Budget
deriving instance Hashable BudgetTransferValue
deriving instance Hashable BudgetTransferType
deriving instance Hashable TaggedAcnt
deriving instance Ord TaggedAcnt
type CurID = T.Text
data Income = Income
{ incGross :: Decimal
, incCurrency :: CurID
, incWhen :: DatePat
, incPretax :: [SingleAllocation PretaxValue]
, incTaxes :: [SingleAllocation TaxValue]
, incPosttax :: [SingleAllocation PosttaxValue]
, incFrom :: TaggedAcnt
, incToBal :: TaggedAcnt
}
deriving instance Hashable Income
deriving instance (Ord w, Ord v) => Ord (Amount w v)
deriving instance Generic (Amount w v)
deriving instance (Generic w, Generic v, FromDhall w, FromDhall v) => FromDhall (Amount w v)
deriving instance (Generic w, Generic v, Hashable w, Hashable v) => Hashable (Amount w v)
deriving instance (Show w, Show v) => Show (Amount w v)
deriving instance (Eq w, Eq v) => Eq (Amount w v)
deriving instance Hashable Exchange
deriving instance Hashable BudgetCurrency
data Allocation w v = Allocation
{ alloTo :: TaggedAcnt
, alloAmts :: [Amount w v]
, alloCur :: CurID
}
deriving (Eq, Show, Generic, Hashable)
instance Bifunctor Amount where
bimap f g a@Amount {amtWhen, amtValue} = a {amtWhen = f amtWhen, amtValue = g amtValue}
instance Bifunctor Allocation where
bimap f g a@Allocation {alloAmts} = a {alloAmts = fmap (bimap f g) alloAmts}
deriving instance (Generic w, Generic v, FromDhall w, FromDhall v) => FromDhall (Allocation w v)
type MultiAllocation = Allocation Interval
type SingleAllocation = Allocation ()
toPersistText :: Show a => a -> PersistValue
toPersistText = PersistText . T.pack . show
fromPersistText :: Read a => T.Text -> PersistValue -> Either T.Text a
fromPersistText what (PersistText t) = case readMaybe $ T.unpack t of
Just v -> Right v
Nothing -> Left $ T.unwords ["error when reading", what, "from text:", t]
fromPersistText what x =
Left $ T.unwords ["error when deserializing", what, "; got", T.pack (show x)]
deriving instance Ord Interval
data Transfer a c w v = Transfer
{ transFrom :: a
, transTo :: a
, transAmounts :: [Amount w v]
, transCurrency :: c
}
deriving (Eq, Show, Generic, FromDhall)
deriving instance
(Generic w, Generic v, Hashable a, Hashable c, Hashable w, Hashable v)
=> Hashable (Transfer a c w v)
deriving instance Hashable ShadowTransfer
deriving instance Hashable AcntSet
deriving instance Hashable TransferMatcher
deriving instance Hashable ValMatcher
deriving instance Hashable YMDMatcher
deriving instance Hashable DateMatcher
deriving instance Ord Decimal
deriving instance Hashable Decimal
-- TODO this just looks silly...but not sure how to simplify it
instance Ord YMDMatcher where
compare (Y y) (Y y') = compare y y'
compare (YM g) (YM g') = compare g g'
compare (YMD g) (YMD g') = compare g g'
compare (Y y) (YM g) = compare y (gmYear g) <> LT
compare (Y y) (YMD g) = compare y (gYear g) <> LT
compare (YM g) (Y y') = compare (gmYear g) y' <> GT
compare (YMD g) (Y y') = compare (gYear g) y' <> GT
compare (YM g) (YMD g') = compare g (gregM g') <> LT
compare (YMD g) (YM g') = compare (gregM g) g' <> GT
gregM :: Gregorian -> GregorianM
gregM Gregorian {gYear = y, gMonth = m} =
GregorianM {gmYear = y, gmMonth = m}
instance Ord DateMatcher where
compare (On d) (On d') = compare d d'
compare (In d r) (In d' r') = compare d d' <> compare r r'
compare (On d) (In d' _) = compare d d' <> LT
compare (In d _) (On d') = compare d d' <> GT
deriving instance Hashable EntryNumGetter
-------------------------------------------------------------------------------
-- top level type with fixed account tree to unroll the recursion in the dhall
-- account tree type
data AccountTree
= Placeholder T.Text T.Text [AccountTree]
| Account T.Text T.Text
deriving (Eq, Generic, Hashable)
TH.makeBaseFunctor ''AccountTree
deriving instance Generic (AccountTreeF a)
deriving instance FromDhall a => FromDhall (AccountTreeF a)
data AccountRoot_ a = AccountRoot_
{ arAssets :: ![a]
, arEquity :: ![a]
, arExpenses :: ![a]
, arIncome :: ![a]
, arLiabilities :: ![a]
}
deriving (Generic)
type AccountRootF = AccountRoot_ (Fix AccountTreeF)
deriving instance FromDhall AccountRootF
type AccountRoot = AccountRoot_ AccountTree
data Config_ a = Config_
{ global :: !TemporalScope
, budget :: ![Budget]
, currencies :: ![Currency]
, statements :: ![History]
, accounts :: !a
, tags :: ![Tag]
, sqlConfig :: !SqlConfig
}
deriving (Generic)
type ConfigF = Config_ AccountRootF
type Config = Config_ AccountRoot
unfix :: ConfigF -> Config
unfix c@Config_ {accounts = a} = c {accounts = a'}
where
a' =
AccountRoot_
{ arAssets = unfixTree arAssets
, arEquity = unfixTree arEquity
, arExpenses = unfixTree arExpenses
, arIncome = unfixTree arIncome
, arLiabilities = unfixTree arLiabilities
}
unfixTree f = foldFix embed <$> f a
instance FromDhall a => FromDhall (Config_ a)
--------------------------------------------------------------------------------
-- dhall type overrides (since dhall can't import types with parameters...yet)
-- TODO newtypes for these?
type AcntID = T.Text
type TagID = T.Text
type HistTransfer = Transfer AcntID CurID DatePat Decimal
data History
= HistTransfer !HistTransfer
| HistStatement !Statement
deriving (Eq, Hashable, Generic, FromDhall)
type EntryGetter = Entry SplitAcnt (Maybe EntryNumGetter) SplitCur TagID
instance FromDhall EntryGetter
deriving instance (Show a, Show c, Show v, Show t) => Show (Entry a v c t)
deriving instance Generic (Entry a v c t)
deriving instance (Hashable a, Hashable v, Hashable c, Hashable t) => Hashable (Entry a v c t)
deriving instance (Eq a, Eq v, Eq c, Eq t) => Eq (Entry a v c t)
data Tx s = Tx
{ txDescr :: !T.Text
, txDate :: !Day
, txSplits :: ![s]
}
deriving (Generic)
type ExpTx = Tx EntryGetter
instance FromDhall ExpTx
data TxOpts re = TxOpts
{ toDate :: !T.Text
, toAmount :: !T.Text
, toDesc :: !T.Text
, toOther :: ![T.Text]
, toDateFmt :: !T.Text
, toAmountFmt :: !re
}
deriving (Eq, Generic, Hashable, Show, FromDhall)
data Statement = Statement
{ stmtPaths :: ![FilePath]
, stmtParsers :: ![StatementParser T.Text]
, stmtDelim :: !Word
, stmtTxOpts :: !(TxOpts T.Text)
, stmtSkipLines :: !Natural
}
deriving (Eq, Hashable, Generic, FromDhall)
-- | the value of a field in split (text version)
-- can either be a raw (constant) value, a lookup from the record, or a map
-- between the lookup and some other value
data EntryTextGetter t
= ConstT !t
| LookupT !T.Text
| MapT !(FieldMap T.Text t)
| Map2T !(FieldMap (T.Text, T.Text) t)
deriving (Eq, Generic, Hashable, Show, FromDhall)
type SplitCur = EntryTextGetter CurID
type SplitAcnt = EntryTextGetter AcntID
deriving instance (Show k, Show v) => Show (Field k v)
deriving instance (Eq k, Eq v) => Eq (Field k v)
deriving instance Generic (Field k v)
deriving instance (Hashable k, Hashable v) => Hashable (Field k v)
deriving instance Foldable (Field k)
deriving instance Traversable (Field k)
deriving instance (FromDhall k, FromDhall v) => FromDhall (Field k v)
instance Functor (Field f) where
fmap f (Field k v) = Field k $ f v
type FieldMap k v = Field k (M.Map k v)
data FieldMatcher re
= Desc !(Field T.Text re)
| Val !(Field T.Text ValMatcher)
deriving (Eq, Hashable, Generic, FromDhall, Functor, Foldable, Traversable)
deriving instance Show (FieldMatcher T.Text)
data TxGetter = TxGetter
{ tgCurrency :: !SplitCur
, tgAcnt :: !SplitAcnt
, tgEntries :: ![EntryGetter]
}
deriving (Eq, Generic, Hashable, Show, FromDhall)
data StatementParser re = StatementParser
{ spDate :: !(Maybe DateMatcher)
, spVal :: !ValMatcher
, spDesc :: !(Maybe re)
, spOther :: ![FieldMatcher re]
, spTx :: !(Maybe TxGetter)
, spTimes :: !(Maybe Natural)
, spPriority :: !Integer
}
deriving (Eq, Generic, Hashable, FromDhall, Functor)
deriving instance Show (StatementParser T.Text)
--------------------------------------------------------------------------------
-- DATABASE MODEL
--------------------------------------------------------------------------------
share
[mkPersist sqlSettings, mkMigrate "migrateAll"]
[persistLowerCase|
CommitR sql=commits
hash Int
type ConfigType
deriving Show Eq
CurrencyR sql=currencies
symbol T.Text
fullname T.Text
deriving Show Eq
TagR sql=tags
symbol T.Text
fullname T.Text
deriving Show Eq
AccountR sql=accounts
name T.Text
fullpath T.Text
desc T.Text
deriving Show Eq
AccountPathR sql=account_paths
parent AccountRId OnDeleteCascade
child AccountRId OnDeleteCascade
depth Int
deriving Show Eq
TransactionR sql=transactions
commit CommitRId OnDeleteCascade
date Day
description T.Text
deriving Show Eq
SplitR sql=splits
transaction TransactionRId OnDeleteCascade
currency CurrencyRId OnDeleteCascade
account AccountRId OnDeleteCascade
memo T.Text
value Rational
deriving Show Eq
TagRelationR sql=tag_relations
split SplitRId OnDeleteCascade
tag TagRId OnDeleteCascade
BudgetLabelR sql=budget_labels
split SplitRId OnDeleteCascade
budgetName T.Text
deriving Show Eq
|]
--------------------------------------------------------------------------------
-- database cache types
data ConfigHashes = ConfigHashes
{ chIncome :: ![Int]
, chExpense :: ![Int]
, chManual :: ![Int]
, chImport :: ![Int]
}
data ConfigType = CTBudget | CTManual | CTImport
deriving (Eq, Show, Read, Enum)
instance PersistFieldSql ConfigType where
sqlType _ = SqlString
instance PersistField ConfigType where
toPersistValue = PersistText . T.pack . show
-- TODO these error messages *might* be good enough?
fromPersistValue (PersistText v) =
maybe (Left $ "could not parse: " <> v) Right $ readMaybe $ T.unpack v
fromPersistValue _ = Left "wrong type"
type AccountMap = M.Map AcntID (AccountRId, AcntSign, AcntType)
type CurrencyMap = M.Map CurID CurrencyRId
type TagMap = M.Map TagID TagRId
data DBState = DBState
{ kmCurrency :: !CurrencyMap
, kmAccount :: !AccountMap
, kmTag :: !TagMap
, kmBudgetInterval :: !Bounds
, kmStatementInterval :: !Bounds
, kmNewCommits :: ![Int]
, kmConfigDir :: !FilePath
}
type MappingT m = ReaderT DBState (SqlPersistT m)
type KeySplit = Entry AccountRId Rational CurrencyRId TagRId
type KeyTx = Tx KeySplit
type TreeR = Tree ([T.Text], AccountRId)
type Balances = M.Map AccountRId Rational
type BalanceM m = ReaderT (MVar Balances) m
class MonadUnliftIO m => MonadFinance m where
askDBState :: (DBState -> a) -> m a
instance MonadUnliftIO m => MonadFinance (ReaderT DBState m) where
askDBState = asks
class MonadUnliftIO m => MonadBalance m where
askBalances :: m (MVar Balances)
withBalances :: (Balances -> m a) -> m a
withBalances f = do
bs <- askBalances
withMVar bs f
modifyBalances :: (Balances -> m (Balances, a)) -> m a
modifyBalances f = do
bs <- askBalances
modifyMVar bs f
lookupBalance :: AccountRId -> m Rational
lookupBalance i = withBalances $ return . fromMaybe 0 . M.lookup i
addBalance :: AccountRId -> Rational -> m ()
addBalance i v =
modifyBalances $ return . (,()) . M.alter (Just . maybe v (v +)) i
-------------------------------------------------------------------------------
-- misc
data AcntType
= AssetT
| EquityT
| ExpenseT
| IncomeT
| LiabilityT
deriving (Show, Eq, Ord, Lift, Hashable, Generic, Read, FromDhall)
atName :: AcntType -> T.Text
atName AssetT = "asset"
atName EquityT = "equity"
atName ExpenseT = "expense"
atName IncomeT = "income"
atName LiabilityT = "liability"
data AcntPath = AcntPath
{ apType :: !AcntType
, apChildren :: ![T.Text]
}
deriving (Eq, Ord, Show, Lift, Hashable, Generic, Read, FromDhall)
data TxRecord = TxRecord
{ trDate :: !Day
, trAmount :: !Rational
, trDesc :: !T.Text
, trOther :: !(M.Map T.Text T.Text)
, trFile :: !FilePath
}
deriving (Show, Eq, Ord)
type Bounds = (Day, Natural)
data Keyed a = Keyed
{ kKey :: !Int64
, kVal :: !a
}
deriving (Eq, Show, Functor)
data Tree a = Branch !a ![Tree a] | Leaf !a deriving (Show)
data AcntSign = Credit | Debit
deriving (Show)
sign2Int :: AcntSign -> Int
sign2Int Debit = 1
sign2Int Credit = 1
accountSign :: AcntType -> AcntSign
accountSign AssetT = Debit
accountSign ExpenseT = Debit
accountSign IncomeT = Credit
accountSign LiabilityT = Credit
accountSign EquityT = Credit
type RawSplit = Entry AcntID (Maybe Rational) CurID TagID
type BalSplit = Entry AcntID Rational CurID TagID
type RawTx = Tx RawSplit
type BalTx = Tx BalSplit
data MatchRes a = MatchPass !a | MatchFail | MatchSkip
--------------------------------------------------------------------------------
-- exception types
data BalanceType = TooFewSplits | NotOneBlank deriving (Show)
data MatchType = MatchNumeric | MatchText deriving (Show)
data SplitIDType = AcntField | CurField | TagField deriving (Show)
data LookupSuberr
= SplitIDField !SplitIDType
| SplitValField
| MatchField !MatchType
| DBKey !SplitIDType
deriving (Show)
data AllocationSuberr
= NoAllocations
| ExceededTotal
| MissingBlank
| TooManyBlanks
deriving (Show)
data PatternSuberr = ZeroLength | ZeroRepeats deriving (Show)
data InsertError
= RegexError !T.Text
| MatchValPrecisionError !Natural !Natural
| AccountError !AcntID !(NE.NonEmpty AcntType)
| InsertIOError !T.Text
| ParseError !T.Text
| ConversionError !T.Text
| LookupError !LookupSuberr !T.Text
| BalanceError !BalanceType !CurID ![RawSplit]
| IncomeError !Day !T.Text !Rational
| PatternError !Natural !Natural !(Maybe Natural) !PatternSuberr
| BoundsError !Gregorian !(Maybe Gregorian)
| StatementError ![TxRecord] ![MatchRe]
deriving (Show)
newtype InsertException = InsertException [InsertError] deriving (Show)
instance Exception InsertException
type EitherErr = Either InsertError
type EitherErrs = Either [InsertError]
data XGregorian = XGregorian
{ xgYear :: !Int
, xgMonth :: !Int
, xgDay :: !Int
, xgDayOfWeek :: !Int
}
type MatchRe = StatementParser (T.Text, Regex)
type TxOptsRe = TxOpts (T.Text, Regex)
type FieldMatcherRe = FieldMatcher (T.Text, Regex)
instance Show (StatementParser (T.Text, Regex)) where
show = show . fmap fst