From 5d2caf3c7f40f8a9e6114db42a7511a1f2aa29a8 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Sun, 11 Jul 2021 10:52:50 -1000
Subject: [PATCH] lib: clarify journalEndDate, add journalLastDay

---
 hledger-lib/Hledger/Data/Journal.hs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index d2e6aacf1..37fc1b3e9 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -60,6 +60,7 @@ module Hledger.Data.Journal (
   journalDateSpanBothDates,
   journalStartDate,
   journalEndDate,
+  journalLastDay,
   journalDescriptions,
   journalFilePath,
   journalFilePaths,
@@ -1316,11 +1317,16 @@ journalDateSpanHelper whichdate j =
 journalStartDate :: Bool -> Journal -> Maybe Day
 journalStartDate secondary j = b where DateSpan b _ = journalDateSpan secondary j
 
--- | The latest of this journal's transaction and posting dates, or
--- Nothing if there are none.
+-- | The "exclusive end date" of this journal: the day following its latest transaction 
+-- or posting date, or Nothing if there are none.
 journalEndDate :: Bool -> Journal -> Maybe Day
 journalEndDate secondary j = e where DateSpan _ e = journalDateSpan secondary j
 
+-- | The latest of this journal's transaction and posting dates, or
+-- Nothing if there are none.
+journalLastDay :: Bool -> Journal -> Maybe Day
+journalLastDay secondary j = addDays (-1) <$> journalEndDate secondary j
+
 -- | Apply the pivot transformation to all postings in a journal,
 -- replacing their account name by their value for the given field or tag.
 journalPivot :: Text -> Journal -> Journal