lib: refactor the raw number parser [API change]
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Alex Chen
Simon Michael
parent
93fbac99d3
commit
121ba92ade
@ -101,12 +101,17 @@ import Control.Monad.State.Strict
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import Data.Bifunctor
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import Data.Char
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import Data.Data
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import Data.Decimal (DecimalRaw (Decimal), Decimal)
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import Data.Default
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import Data.Functor.Identity
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import Data.List.Compat
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import Data.List.NonEmpty (NonEmpty(..))
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import Data.Maybe
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#if !(MIN_VERSION_base(4,11,0))
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import Data.Monoid
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#endif
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import qualified Data.Map as M
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import qualified Data.Semigroup as Sem
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import Data.Text (Text)
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import qualified Data.Text as T
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import Data.Time.Calendar
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@ -709,93 +714,201 @@ exponentp = do
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return $ bimap (* 10^^exp) (max 0 . subtract exp)
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<?> "exponentp"
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-- | Interpret the raw parts of a number, using the provided amount style if any,
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-- determining the decimal point character and digit groups where possible.
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-- | Interpret a raw number as a decimal number, and identify the decimal
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-- point charcter and digit separating scheme. There is only one ambiguous
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-- case: when there is just a single separator between two digit groups.
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-- Disambiguate using an amount style, if provided; otherwise, assume that
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-- the separator is a decimal point.
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--
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-- Returns:
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-- - the decimal number
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-- - the precision (number of digits after the decimal point)
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-- - the decimal point character, if any
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-- - the digit group style, if any (digit group character and sizes of digit groups)
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fromRawNumber :: Maybe AmountStyle -> Bool -> (Maybe Char, [String], Maybe (Char, String)) -> (Quantity, Int, Maybe Char, Maybe DigitGroupStyle)
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fromRawNumber suggestedStyle negated raw = (quantity, precision, mdecimalpoint, mgrps) where
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-- unpack with a hint if useful
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(mseparator, intparts, mdecimalpoint, frac) =
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case raw of
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-- If the number consists of exactly two digit groups
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-- separated by a valid decimal point character, we assume
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-- that the character represents a decimal point.
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(Just s, [firstGroup, lastGroup], Nothing)
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| s `elem` decimalPointChars && maybe True (`asdecimalcheck` s) suggestedStyle ->
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(Nothing, [firstGroup], Just s, lastGroup)
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fromRawNumber
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:: Maybe AmountStyle
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-> Bool
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-> RawNumber
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-> (Quantity, Int, Maybe Char, Maybe DigitGroupStyle)
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fromRawNumber suggestedStyle negated raw = case raw of
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(firstSep, digitGroups, Nothing) -> (firstSep, digitGroups, Nothing, [])
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(firstSep, digitGroups, Just (d, frac)) -> (firstSep, digitGroups, Just d, frac)
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LeadingDecimalPt decPt digitGrp ->
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let quantity = sign $ Decimal (fromIntegral precision)
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(digitGroupNumber digitGrp)
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precision = digitGroupLength digitGrp
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in (quantity, precision, Just decPt, Nothing)
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-- get the digit group sizes and digit group style if any
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groupsizes = reverse $ case map length intparts of
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(a:b:cs) | a < b -> b:cs
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gs -> gs
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mgrps = (`DigitGroups` groupsizes) <$> mseparator
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TrailingDecimalPt digitGrp decPt ->
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let quantity = sign $ Decimal (fromIntegral precision)
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(digitGroupNumber digitGrp)
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precision = 0
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in (quantity, precision, Just decPt, Nothing)
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-- put the parts back together without digit group separators, get the precision and parse the value
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repr = (if negated then "-" else "") ++ "0" ++ concat intparts ++ (if null frac then "" else "." ++ frac)
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quantity = read repr
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precision = length frac
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NoSeparators digitGrp ->
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let quantity = sign $ Decimal (fromIntegral precision)
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(digitGroupNumber digitGrp)
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precision = 0
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in (quantity, precision, Nothing, Nothing)
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asdecimalcheck :: AmountStyle -> Char -> Bool
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asdecimalcheck = \case
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AmountStyle{asdecimalpoint = Just d} -> (d ==)
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AmountStyle{asdigitgroups = Just (DigitGroups g _)} -> (g /=)
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AmountStyle{asprecision = 0} -> const False
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_ -> const True
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AmbiguousNumber digitGrp1 sep digitGrp2 ->
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-- If present, use the suggested style to disambiguate;
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-- otherwise, assume that the separator is a decimal point where possible.
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if isDecimalPointChar sep && maybe True (sep `isValidDecimalBy`) suggestedStyle
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-- | Pre-parse a number into parts for further interpretation.
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-- Numbers may optionally have a period/comma decimal point
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-- and/or comma/period/space digit group separators, but we don't
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-- decide which is which here, just return the parts:
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then -- Assuming that the separator is a decimal point
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let quantity = sign $ Decimal (fromIntegral precision)
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(digitGroupNumber $ digitGrp1 <> digitGrp2)
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precision = digitGroupLength digitGrp2
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in (quantity, precision, Just sep, Nothing)
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else -- Assuming that the separator is digit separator
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let quantity = sign $ Decimal (fromIntegral precision)
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(digitGroupNumber $ digitGrp1 <> digitGrp2)
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precision = 0
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digitGroupStyle = Just $
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DigitGroups sep (groupSizes $ [digitGrp1, digitGrp2])
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in (quantity, precision, Nothing, digitGroupStyle)
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DigitSeparators digitSep digitGrps ->
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let quantity = sign $ Decimal (fromIntegral precision)
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(digitGroupNumber $ mconcat digitGrps)
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precision = 0
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digitGroupStyle = Just $ DigitGroups digitSep (groupSizes digitGrps)
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in (quantity, precision, Nothing, digitGroupStyle)
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BothSeparators digitSep digitGrps decPt decimalGrp ->
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let quantity =
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sign $ Decimal (fromIntegral precision)
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(digitGroupNumber $ mconcat digitGrps <> decimalGrp)
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precision = digitGroupLength decimalGrp
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digitGroupStyle = Just $ DigitGroups digitSep (groupSizes digitGrps)
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in (quantity, precision, Just decPt, digitGroupStyle)
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where
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sign :: Decimal -> Decimal
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sign = if negated then negate else id
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-- Outputs digit group sizes from least significant to most significant
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groupSizes :: [DigitGrp] -> [Int]
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groupSizes digitGrps = reverse $ case map digitGroupLength digitGrps of
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(a:b:cs) | a < b -> b:cs
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gs -> gs
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isValidDecimalBy :: Char -> AmountStyle -> Bool
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isValidDecimalBy c = \case
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AmountStyle{asdecimalpoint = Just d} -> d == c
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AmountStyle{asdigitgroups = Just (DigitGroups g _)} -> g /= c
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AmountStyle{asprecision = 0} -> False
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_ -> True
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-- | Parse and interpret the structure of a number as far as possible
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-- without external hints. Numbers are digit strings, possibly separated
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-- into digit groups by one of two types of separators. (1) Numbers may
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-- optionally have a decimal point, which may be either a period or comma.
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-- (2) Numbers may optionally contain digit group separators, which must
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-- all be either a period, a comma, or a space.
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--
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-- - the first separator char (period or comma or space) seen, if any
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--
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-- - the digit group(s), possibly several separated by the above char, occuring before..
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--
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-- - the second and last separator char, and following digit group, if any.
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-- It is our task to deduce the identities of the decimal point and digit
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-- separator characters, based on the allowed syntax. For instance, we
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-- make use of the fact that a decimal point can occur at most once and
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-- must succeed all digit group separators.
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--
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-- >>> parseTest rawnumberp "1,234,567.89"
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-- (Just ',',["1","234","567"],Just ('.',"89"))
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-- BothSeparators ',' ["1","234","567"] '.' "89"
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-- >>> parseTest rawnumberp "1 000"
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-- (Just ' ',["1","000"],Nothing)
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rawnumberp :: TextParser m ( Maybe Char , [String] , Maybe (Char, String) )
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rawnumberp = do
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(firstSep, groups) <- option (Nothing, []) $ do
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leadingDigits <- some digitChar
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option (Nothing, [leadingDigits]) . try $ do
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firstSep <- oneOf decimalPointChars <|> whitespaceChar
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secondGroup <- some digitChar
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otherGroups <- many $ try $ char firstSep *> some digitChar
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return (Just firstSep, leadingDigits : secondGroup : otherGroups)
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-- AmbiguousNumber "1" ' ' "000"
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--
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rawnumberp :: TextParser m RawNumber
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rawnumberp = label "rawnumberp" $ do
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rawNumber <- leadingDecimalPt <|> leadingDigits
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let remSepChars = maybe decimalPointChars (`delete` decimalPointChars) firstSep
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modifier
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| null groups = fmap Just -- if no digits so far, we require at least some decimals
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| otherwise = optional
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-- Guard against mistyped numbers
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notFollowedBy $ satisfy isDecimalPointChar <|> (char ' ' >> digitChar)
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extraGroup <- modifier $ do
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lastSep <- oneOf remSepChars
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digits <- modifier $ some digitChar -- decimal separator allowed to be without digits if had some before
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return (lastSep, fromMaybe [] digits)
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return $ dbg8 "rawnumberp" rawNumber
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-- make sure we didn't leading part of mistyped number
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notFollowedBy $ oneOf decimalPointChars <|> (whitespaceChar >> digitChar)
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where
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return $ dbg8 "rawnumberp" (firstSep, groups, extraGroup)
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<?> "rawnumberp"
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leadingDecimalPt :: TextParser m RawNumber
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leadingDecimalPt =
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LeadingDecimalPt <$> satisfy isDecimalPointChar <*> pdigitgroup
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decimalPointChars :: String
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decimalPointChars = ".,"
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leadingDigits :: TextParser m RawNumber
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leadingDigits = do
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grp1 <- pdigitgroup
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withSeparators grp1 <|> trailingDecimalPt grp1 <|> pure (NoSeparators grp1)
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-- | Parse a unicode char that represents any non-control space char (Zs general category).
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whitespaceChar :: TextParser m Char
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whitespaceChar = charCategory Space
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withSeparators :: DigitGrp -> TextParser m RawNumber
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withSeparators grp1 = do
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(sep, grp2) <- try $ (,) <$> satisfy isDigitSeparatorChar <*> pdigitgroup
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grps <- many $ try $ char sep *> pdigitgroup
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let digitGroups = grp1 : grp2 : grps
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withDecimalPt sep digitGroups <|> pure (withoutDecimalPt grp1 sep grp2 grps)
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withDecimalPt :: Char -> [DigitGrp] -> TextParser m RawNumber
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withDecimalPt digitSep digitGroups = do
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decimalPt <- satisfy $ \c -> isDecimalPointChar c && c /= digitSep
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decimalDigitGroup <- option mempty pdigitgroup
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pure $ BothSeparators digitSep digitGroups decimalPt decimalDigitGroup
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withoutDecimalPt :: DigitGrp -> Char -> DigitGrp -> [DigitGrp] -> RawNumber
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withoutDecimalPt grp1 sep grp2 grps
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| null grps = AmbiguousNumber grp1 sep grp2
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| otherwise = DigitSeparators sep (grp1:grp2:grps)
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trailingDecimalPt :: DigitGrp -> TextParser m RawNumber
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trailingDecimalPt grp1 = do
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decimalPt <- satisfy isDecimalPointChar
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pure $ TrailingDecimalPt grp1 decimalPt
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isDecimalPointChar :: Char -> Bool
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isDecimalPointChar c = c == '.' || c == ','
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isDigitSeparatorChar :: Char -> Bool
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isDigitSeparatorChar c = isDecimalPointChar c || c == ' '
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data DigitGrp = DigitGrp {
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digitGroupLength :: Int,
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digitGroupNumber :: Integer
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} deriving (Eq)
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instance Show DigitGrp where
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show (DigitGrp len num)
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| len > 0 = "\"" ++ padding ++ numStr ++ "\""
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| otherwise = "\"\""
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where numStr = show num
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padding = replicate (len - length numStr) '0'
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instance Sem.Semigroup DigitGrp where
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DigitGrp l1 n1 <> DigitGrp l2 n2 = DigitGrp (l1 + l2) (n1 * 10^l2 + n2)
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instance Monoid DigitGrp where
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mempty = DigitGrp 0 0
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mappend = (Sem.<>)
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pdigitgroup :: TextParser m DigitGrp
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pdigitgroup = label "digit group"
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$ makeGroup <$> takeWhile1P (Just "digit") isDigit
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where
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makeGroup = uncurry DigitGrp . foldl' step (0, 0) . T.unpack
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step (!l, !a) c = (l+1, a*10 + fromIntegral (digitToInt c))
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data RawNumber
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= LeadingDecimalPt Char DigitGrp -- .50
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| TrailingDecimalPt DigitGrp Char -- 100.
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| NoSeparators DigitGrp -- 100
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| AmbiguousNumber DigitGrp Char DigitGrp -- 1,000
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| DigitSeparators Char [DigitGrp] -- 1,000,000
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| BothSeparators Char [DigitGrp] Char DigitGrp -- 1,000.50
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deriving (Show, Eq)
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-- test_numberp = do
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-- let s `is` n = assertParseEqual (parseWithState mempty numberp s) n
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