draft of account historical balance calculation

gistfile1.hs

-- Reports.hs:

-- | Get the historical running inclusive balance of a particular account,
-- from earliest to latest posting date.
-- XXX Accounts should know the Ledger & Journal they came from
accountBalanceHistory :: ReportOpts -> Journal -> Account -> [(Day, MixedAmount)]
accountBalanceHistory ropts j a = [(getdate t, bal) | (t,_,_,_,_,bal) <- items]
  where
    (_,items) = journalTransactionsReport ropts j acctquery
    inclusivebal = True
    acctquery = Acct $ (if inclusivebal then accountNameToAccountRegex else accountNameToAccountOnlyRegex) $ aname a
    getdate = if effective_ ropts then transactionEffectiveDate else transactionActualDate