ui: clarify docs of some period functions

This commit is contained in:
Simon Michael 2016-12-07 14:54:23 -08:00
parent 91c524b600
commit 6aeaee17f5

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@ -143,7 +143,8 @@ periodEnd p = me
where
DateSpan _ me = periodAsDateSpan p
-- | Move a period to the following period of same duration.
-- | Move a standard period (day, week, month etc.) to the following period of same duration.
-- Non-standard periods are unaffected.
periodNext :: Period -> Period
periodNext (DayPeriod b) = DayPeriod (addDays 1 b)
periodNext (WeekPeriod b) = WeekPeriod (addDays 7 b)
@ -154,7 +155,8 @@ periodNext (QuarterPeriod y q) = QuarterPeriod y (q+1)
periodNext (YearPeriod y) = YearPeriod (y+1)
periodNext p = p
-- | Move a period to the preceding period of same duration.
-- | Move a standard period (day, week, month etc.) to the preceding period of same duration.
-- Non-standard periods are unaffected.
periodPrevious :: Period -> Period
periodPrevious (DayPeriod b) = DayPeriod (addDays (-1) b)
periodPrevious (WeekPeriod b) = WeekPeriod (addDays (-7) b)
@ -165,7 +167,8 @@ periodPrevious (QuarterPeriod y q) = QuarterPeriod y (q-1)
periodPrevious (YearPeriod y) = YearPeriod (y-1)
periodPrevious p = p
-- | Move a period to the following period of same duration, staying within enclosing dates.
-- | Move a standard period to the following period of same duration, staying within enclosing dates.
-- Non-standard periods are unaffected.
periodNextIn :: DateSpan -> Period -> Period
periodNextIn (DateSpan _ (Just e)) p =
case mb of
@ -176,7 +179,8 @@ periodNextIn (DateSpan _ (Just e)) p =
mb = periodStart p'
periodNextIn _ p = periodNext p
-- | Move a period to the preceding period of same duration, staying within enclosing dates.
-- | Move a standard period to the preceding period of same duration, staying within enclosing dates.
-- Non-standard periods are unaffected.
periodPreviousIn :: DateSpan -> Period -> Period
periodPreviousIn (DateSpan (Just b) _) p =
case me of
@ -187,7 +191,8 @@ periodPreviousIn (DateSpan (Just b) _) p =
me = periodEnd p'
periodPreviousIn _ p = periodPrevious p
-- | Move a period stepwise so that it encloses the given date.
-- | Move a standard period stepwise so that it encloses the given date.
-- Non-standard periods are unaffected.
periodMoveTo :: Day -> Period -> Period
periodMoveTo d (DayPeriod _) = DayPeriod d
periodMoveTo d (WeekPeriod _) = WeekPeriod $ mondayBefore d
@ -203,7 +208,7 @@ periodMoveTo _ p = p
-- Eg, a day becomes the enclosing week.
-- A week becomes whichever month the week's thursday falls into.
-- A year becomes all (unlimited).
-- Growing an unlimited period, or a non-standard period (arbitrary dates) has no effect.
-- Non-standard periods (arbitrary dates, or open-ended) are unaffected.
periodGrow :: Period -> Period
periodGrow (DayPeriod b) = WeekPeriod $ mondayBefore b
periodGrow (WeekPeriod b) = MonthPeriod y m