Haspara.Date

This module provides definitions and functions to encode and work on date values.

Date

Definition

data Date

Type encoding for date values.

This is a convenience wrapper around Day type. It helps us to avoid defining orphan instances.

Instances

Enum Date

Defined in Haspara.Internal.Date

Methods

succ :: Date -> Date

pred :: Date -> Date

toEnum :: Int -> Date

fromEnum :: Date -> Int

enumFrom :: Date -> [Date]

enumFromThen :: Date -> Date -> [Date]

enumFromTo :: Date -> Date -> [Date]

enumFromThenTo :: Date -> Date -> Date -> [Date]

Eq Date

Defined in Haspara.Internal.Date

Methods

(==) :: Date -> Date -> Bool

(/=) :: Date -> Date -> Bool

Ord Date

Defined in Haspara.Internal.Date

Methods

compare :: Date -> Date -> Ordering

(<) :: Date -> Date -> Bool

(<=) :: Date -> Date -> Bool

(>) :: Date -> Date -> Bool

(>=) :: Date -> Date -> Bool

max :: Date -> Date -> Date

min :: Date -> Date -> Date

Read Date

Read instance for Date.

>>> read "2021-01-01" :: Date
2021-01-01
>>> read "Just 2021-01-01" :: Maybe Date
Just 2021-01-01

Defined in Haspara.Internal.Date

Methods

readsPrec :: Int -> ReadS Date

readList :: ReadS [Date]

readPrec :: ReadPrec Date

readListPrec :: ReadPrec [Date]

Show Date

Show instance for Date.

>>> fromYMD 2020 12 31
2020-12-31

Defined in Haspara.Internal.Date

Methods

showsPrec :: Int -> Date -> ShowS

show :: Date -> String

showList :: [Date] -> ShowS

Hashable Date

Hashable instance for Date.

Defined in Haspara.Internal.Date

Methods

hashWithSalt :: Int -> Date -> Int

hash :: Date -> Int

ToJSON Date

ToJSON instance for Date.

>>> Aeson.encode (MkDate (read "2021-01-01"))
"\"2021-01-01\""

Defined in Haspara.Internal.Date

Methods

toJSON :: Date -> Value

toEncoding :: Date -> Encoding

toJSONList :: [Date] -> Value

toEncodingList :: [Date] -> Encoding

FromJSON Date

FromJSON instance for Date.

>>> Aeson.decode "\"2020-12-31\"" :: Maybe Date
Just 2020-12-31

Defined in Haspara.Internal.Date

Methods

parseJSON :: Value -> Parser Date

parseJSONList :: Value -> Parser [Date]

Constructors

fromDay :: Day -> Date

Builds a Date from a given Day.

>>> fromDay (read "2021-01-01")
2021-01-01

fromYMD :: Integer -> Int -> Int -> Date

Builds a Date from a given year, month and day as in Gregorian calendar.

>>> fromYMD 2021 1 1
2021-01-01

fromString :: MonadFail m => String -> m Date

Attempts to parse and return Date from a given String with ISO format.

>>> fromString "2021-01-01" :: Maybe Date
Just 2021-01-01
>>> fromString "20210101" :: Maybe Date
Nothing

fromFormattedString :: MonadFail m => String -> String -> m Date

Attempts to parse and return Date from a given String with given date format.

>>> fromFormattedString "%Y-%m-%d" "2021-01-01" :: Maybe Date
Just 2021-01-01
>>> fromFormattedString "%Y%m%d" "20210101" :: Maybe Date
Just 2021-01-01
>>> fromFormattedString "%Y%m%d" "202101" :: Maybe Date
Nothing

fromText :: MonadFail m => Text -> m Date

Attempts to parse and return Date from a given Text with ISO format.

>>> fromText "2021-01-01" :: Maybe Date
Just 2021-01-01
>>> fromText "20210101" :: Maybe Date
Nothing

fromFormattedText :: MonadFail m => String -> Text -> m Date

Attempts to parse and return Date from a given Text with ISO format.

>>> fromFormattedText "%Y-%m-%d" "2021-01-01" :: Maybe Date
Just 2021-01-01
>>> fromFormattedText "%Y%m%d" "20210101" :: Maybe Date
Just 2021-01-01
>>> fromFormattedText "%Y%m%d" "202101" :: Maybe Date
Nothing

Conversions

toDay :: Date -> Day

Converts Date value to a Day value.

>>> toDay (read "2021-01-01")
2021-01-01

toYMD :: Date -> (Integer, Int, Int)

Converts Date value to a 3-tuple of year, month and day.

>>> toYMD (read "2020-12-31")
(2020,12,31)

toString :: Date -> String

Converts Date value into a String value with ISO format.

>>> toString (read "2021-01-01")
"2021-01-01"

toFormattedString :: String -> Date -> String

Converts Date value into a String value with the given format.

>>> toFormattedString "%Y-%m-%d" (read "2021-01-01")
"2021-01-01"
>>> toFormattedString "%d/%m/%Y" (read "2021-01-01")
"01/01/2021"

toText :: Date -> Text

Converts Date value into a Text value with ISO format.

>>> toText (read "2021-01-01")
"2021-01-01"

toFormattedText :: String -> Date -> Text

Converts Date value into a Text value with the given format.

>>> toFormattedText "%Y-%m-%d" (read "2021-01-01")
"2021-01-01"
>>> toFormattedText "%d/%m/%Y" (read "2021-01-01")
"01/01/2021"

Operations

addDays :: Integer -> Date -> Date

Adds (or subtracts) some days.

>>> addDays (-1) $ fromYMD 2021 1 1
2020-12-31
>>> addDays 1 $ addDays (-1) $ fromYMD 2021 1 1
2021-01-01