Hledger.Data.Dates

Date parsing and utilities for hledger.

For date and time values, we use the standard Day and UTCTime types.

A SmartDate is a date which may be partially-specified or relative. Eg 2008/12/31, but also 2008/12, 12/31, tomorrow, last week, next year. We represent these as a triple of strings like ("2008","12",""), ("","","tomorrow"), ("","last","week").

A DateSpan is the span of time between two specific calendar dates, or an open-ended span where one or both dates are unspecified. (A date span with both ends unspecified matches all dates.)

An Interval is ledger's "reporting interval" - weekly, monthly, quarterly, etc.

Period will probably replace DateSpan in due course.

Misc date handling utilities

getCurrentDay :: IO Day

Get the current local date.

getCurrentMonth :: IO Int

Get the current local month number.

getCurrentYear :: IO Integer

Get the current local year.

nulldate :: Day

spanContainsDate :: DateSpan -> Day -> Bool

Does the span include the given date ?

parsedateM :: String -> Maybe Day

Parse a couple of date string formats to a time type.

parsedate :: String -> Day

Parse a YYYY-MM-DD or YYYYMMDD date string to a Day, or raise an error. For testing/debugging.

>>> parsedate "2008/02/03"
2008-02-03

showDate :: Day -> String

showDateSpan :: DateSpan -> String

Render a datespan as a display string, abbreviating into a compact form if possible.

elapsedSeconds :: Fractional a => UTCTime -> UTCTime -> a

prevday :: Day -> Day

parsePeriodExpr :: Day -> Text -> Either (ParseError Char Dec) (Interval, DateSpan)

Parse a period expression to an Interval and overall DateSpan using the provided reference date, or return a parse error.

nulldatespan :: DateSpan

failIfInvalidYear :: Monad m => String -> m ()

failIfInvalidMonth :: Monad m => String -> m ()

failIfInvalidDay :: Monad m => String -> m ()

datesepchar :: TextParser m Char

datesepchars :: [Char]

spanStart :: DateSpan -> Maybe Day

spanEnd :: DateSpan -> Maybe Day

spansSpan :: [DateSpan] -> DateSpan

Get overall span enclosing multiple sequentially ordered spans.

spanIntersect :: DateSpan -> DateSpan -> DateSpan

Calculate the intersection of two datespans.

spansIntersect :: [DateSpan] -> DateSpan

Calculate the intersection of a number of datespans.

spanDefaultsFrom :: DateSpan -> DateSpan -> DateSpan

Fill any unspecified dates in the first span with the dates from the second one. Sort of a one-way spanIntersect.

spanUnion :: DateSpan -> DateSpan -> DateSpan

Calculate the union of two datespans.

spansUnion :: [DateSpan] -> DateSpan

Calculate the union of a number of datespans.

smartdate :: Parser SmartDate

Parse a date in any of the formats allowed in ledger's period expressions, and maybe some others:

2004
2004/10
2004/10/1
10/1
21
october, oct
yesterday, today, tomorrow
this/next/last week/day/month/quarter/year

Returns a SmartDate, to be converted to a full date later (see fixSmartDate). Assumes any text in the parse stream has been lowercased.

splitSpan :: Interval -> DateSpan -> [DateSpan]

Split a DateSpan into one or more consecutive whole spans of the specified length which enclose it. If no interval is specified, the original span is returned.

Examples:

>>> let t i d1 d2 = splitSpan i $ mkdatespan d1 d2
>>> t NoInterval "2008/01/01" "2009/01/01"
[DateSpan 2008]
>>> t (Quarters 1) "2008/01/01" "2009/01/01"
[DateSpan 2008q1,DateSpan 2008q2,DateSpan 2008q3,DateSpan 2008q4]
>>> splitSpan (Quarters 1) nulldatespan
[DateSpan -]
>>> t (Days 1) "2008/01/01" "2008/01/01"  -- an empty datespan
[DateSpan 2008/01/01-2007/12/31]
>>> t (Quarters 1) "2008/01/01" "2008/01/01"
[DateSpan 2008/01/01-2007/12/31]
>>> t (Months 1) "2008/01/01" "2008/04/01"
[DateSpan 2008/01,DateSpan 2008/02,DateSpan 2008/03]
>>> t (Months 2) "2008/01/01" "2008/04/01"
[DateSpan 2008/01/01-2008/02/29,DateSpan 2008/03/01-2008/04/30]
>>> t (Weeks 1) "2008/01/01" "2008/01/15"
[DateSpan 2007/12/31w01,DateSpan 2008/01/07w02,DateSpan 2008/01/14w03]
>>> t (Weeks 2) "2008/01/01" "2008/01/15"
[DateSpan 2007/12/31-2008/01/13,DateSpan 2008/01/14-2008/01/27]
>>> t (DayOfMonth 2) "2008/01/01" "2008/04/01"
[DateSpan 2008/01/02-2008/02/01,DateSpan 2008/02/02-2008/03/01,DateSpan 2008/03/02-2008/04/01]
>>> t (DayOfWeek 2) "2011/01/01" "2011/01/15"
[DateSpan 2011/01/04-2011/01/10,DateSpan 2011/01/11-2011/01/17]

fixSmartDate :: Day -> SmartDate -> Day

Convert a SmartDate to an absolute date using the provided reference date.

Examples:

>>> let t = fixSmartDateStr (parsedate "2008/11/26")
>>> t "0000-01-01"
"0000/01/01"
>>> t "1999-12-02"
"1999/12/02"
>>> t "1999.12.02"
"1999/12/02"
>>> t "1999/3/2"
"1999/03/02"
>>> t "19990302"
"1999/03/02"
>>> t "2008/2"
"2008/02/01"
>>> t "0020/2"
"0020/02/01"
>>> t "1000"
"1000/01/01"
>>> t "4/2"
"2008/04/02"
>>> t "2"
"2008/11/02"
>>> t "January"
"2008/01/01"
>>> t "feb"
"2008/02/01"
>>> t "today"
"2008/11/26"
>>> t "yesterday"
"2008/11/25"
>>> t "tomorrow"
"2008/11/27"
>>> t "this day"
"2008/11/26"
>>> t "last day"
"2008/11/25"
>>> t "next day"
"2008/11/27"
>>> t "this week"  -- last monday
"2008/11/24"
>>> t "last week"  -- previous monday
"2008/11/17"
>>> t "next week"  -- next monday
"2008/12/01"
>>> t "this month"
"2008/11/01"
>>> t "last month"
"2008/10/01"
>>> t "next month"
"2008/12/01"
>>> t "this quarter"
"2008/10/01"
>>> t "last quarter"
"2008/07/01"
>>> t "next quarter"
"2009/01/01"
>>> t "this year"
"2008/01/01"
>>> t "last year"
"2007/01/01"
>>> t "next year"
"2009/01/01"

t "last wed" "20081119" t "next friday" "20081128" t "next january" "20090101"

fixSmartDateStr :: Day -> Text -> String

Convert a smart date string to an explicit yyyy/mm/dd string using the provided reference date, or raise an error.

fixSmartDateStrEither :: Day -> Text -> Either (ParseError Char Dec) String

A safe version of fixSmartDateStr.

fixSmartDateStrEither' :: Day -> Text -> Either (ParseError Char Dec) Day

daysInSpan :: DateSpan -> Maybe Integer

Count the days in a DateSpan, or if it is open-ended return Nothing.

maybePeriod :: Day -> Text -> Maybe (Interval, DateSpan)

mkdatespan :: String -> String -> DateSpan

Make a datespan from two valid date strings parseable by parsedate (or raise an error). Eg: mkdatespan "201111" "20111231".

Orphan instances

Show DateSpan

Methods

showsPrec :: Int -> DateSpan -> ShowS

show :: DateSpan -> String

showList :: [DateSpan] -> ShowS