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.

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 date string to a time type, or raise an error.

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 -> String -> Either ParseError (Interval, DateSpan)

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

nulldatespan :: DateSpan

tests_Hledger_Data_Dates :: Test

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

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

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

datesepchar :: Stream [Char] m Char => ParsecT [Char] st 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 :: Stream [Char] m Char => ParsecT [Char] st m 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.

fixSmartDate :: Day -> SmartDate -> Day

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

fixSmartDateStr :: Day -> String -> String

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

fixSmartDateStrEither :: Day -> String -> Either ParseError String

A safe version of fixSmartDateStr.

fixSmartDateStrEither' :: Day -> String -> Either ParseError Day

daysInSpan :: DateSpan -> Maybe Integer

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

maybePeriod :: Day -> String -> 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".