lib: valueTypeFromOpts helper

hledger-lib/Hledger/Reports/BalanceReport.hs

@@ -75,7 +75,7 @@ balanceReport ropts@ReportOpts{..} q j =
       --  transaction: value each posting at posting date before summing
       --  period:      value totals at period end
       --  date:        value totals at date
-      mvalueat = if value_ then Just value_at_ else Nothing
+      mvalueat = valueTypeFromOpts ropts
       today    = fromMaybe (error' "balanceReport: ReportOpts today_ is unset so could not satisfy --value-at=now") today_
 
       -- For --value-at=transaction, convert all postings to value before summing them.

hledger-lib/Hledger/Reports/MultiBalanceReports.hs

@@ -154,7 +154,7 @@ multiBalanceReport ropts@ReportOpts{..} q j =
       --   transaction: sum/average the valued amounts
       --   period:      sum/average the unvalued amounts and value at report period end
       --   date:        sum/average the unvalued amounts and value at date
-      mvalueat = if value_ then Just value_at_ else Nothing
+      mvalueat = valueTypeFromOpts ropts
       today    = fromMaybe (error' "postingsReport: ReportOpts today_ is unset so could not satisfy --value-at=now") today_
       -- Market prices. Sort into date then parse order,
       -- & reverse for quick lookup of the latest price.

hledger-lib/Hledger/Reports/PostingsReport.hs

@@ -87,7 +87,7 @@ postingsReport ropts@ReportOpts{..} q j =
       --
       --  "Day before report start" is a bit arbitrary.
 
-      mvalueat = if value_ then Just value_at_ else Nothing
+      mvalueat = valueTypeFromOpts ropts
       today = fromMaybe (error' "postingsReport: ReportOpts today_ is unset so could not satisfy --value-at=now") today_
 
       -- Postings or summary pseudo postings to be displayed.

hledger-lib/Hledger/Reports/ReportOptions.hs

@@ -15,6 +15,7 @@ module Hledger.Reports.ReportOptions (
   defreportopts,
   rawOptsToReportOpts,
   checkReportOpts,
+  valueTypeFromOpts,
   flat_,
   tree_,
   reportOptsToggleStatus,
@@ -84,8 +85,8 @@ instance Default AccountListMode where def = ALDefault
 data ValueDate =
     AtTransaction  -- ^ Calculate values as of each posting's date (called "transaction" for UI reasons)
   | AtPeriod       -- ^ Calculate values as of each report period's last day
-  | AtNow          -- ^ Calculate values as of today (report generation date) (called "now" not today for UI reasons)
-  | AtDate Day     -- ^ Calculate values as of some other date
+  | AtNow          -- ^ Calculate values as of today (report generation date) (called "now" for UI reasons)
+  | AtDate Day     -- ^ Calculate values as of some fixed date
   deriving (Show,Data,Eq) -- Typeable
 
 instance Default ValueDate where def = AtNow
@@ -396,6 +397,18 @@ flat_ = (==ALFlat) . accountlistmode_
 -- depthFromOpts :: ReportOpts -> Int
 -- depthFromOpts opts = min (fromMaybe 99999 $ depth_ opts) (queryDepth $ queryFromOpts nulldate opts)
 
+-- | A simpler way to find the type of valuation to be done, if any.
+-- Considers the --value and --value-at flagsvalueTypeFromOpts :: ReportOpts -> Maybe ValueDate
+valueTypeFromOpts ReportOpts{..} =
+  case (value_, value_at_) of
+    (False,_)     -> Nothing
+    -- (True, AtNow) -> Just $ AtDate (fromMaybe (error' "could not satisfy --value-at=now, expected ReportOpts today_ to be set") today_)
+-- , and converts --value-at=now
+-- to --value-at=DATE so you don't have to mess with today's date.
+-- Ie this will never return AtNow.
+-- (But this is not reflected in the type, or relied on by other code; XXX WIP).
+    (True, vd)    -> Just vd
+
 -- | Convert this journal's postings' amounts to the cost basis amounts if
 -- specified by options.
 journalSelectingAmountFromOpts :: ReportOpts -> Journal -> Journal