hledger/hledger-lib/Hledger/Read/JournalReader.hs

--- * doc
-- Lines beginning "--- *" are collapsible orgstruct nodes. Emacs users,
-- (add-hook 'haskell-mode-hook
--   (lambda () (set-variable 'orgstruct-heading-prefix-regexp "--- " t))
--   'orgstruct-mode)
-- and press TAB on nodes to expand/collapse.

{-|

A reader for hledger's journal file format
(<http://hledger.org/MANUAL.html#the-journal-file>).  hledger's journal
format is a compatible subset of c++ ledger's
(<http://ledger-cli.org/3.0/doc/ledger3.html#Journal-Format>), so this
reader should handle many ledger files as well. Example:

@
2012\/3\/24 gift
    expenses:gifts  $10
    assets:cash
@

-}

--- * module

-- {-# OPTIONS_GHC -F -pgmF htfpp #-}

{-# LANGUAGE CPP, RecordWildCards, NoMonoLocalBinds, ScopedTypeVariables, FlexibleContexts, TupleSections #-}

module Hledger.Read.JournalReader (

--- * exports

  -- * Reader
  reader,

  -- * Parsing utils
  genericSourcePos,
  parseAndFinaliseJournal,

  -- * Parsers used elsewhere
  getParentAccount,
  journalp,
  directivep,
  defaultyeardirectivep,
  marketpricedirectivep,
  datetimep,
  datep,
  codep,
  accountnamep,
  modifiedaccountnamep,
  postingp,
  amountp,
  amountp',
  mamountp',
  numberp,
  statusp,
  emptyorcommentlinep,
  followingcommentp,
  accountaliasp
  -- * Tests
  ,tests_Hledger_Read_JournalReader
#ifdef TESTS
  -- disabled by default, HTF not available on windows
  ,htf_thisModulesTests
  ,htf_Hledger_Read_JournalReader_importedTests
#endif
)
where
--- * imports
import Prelude ()
import Prelude.Compat hiding (readFile)
import qualified Control.Exception as C
import Control.Monad.Compat
import Control.Monad.Except (ExceptT(..), liftIO, runExceptT, throwError, catchError)
import Data.Char (isNumber)
import Data.Functor.Identity
import Data.List.Compat
import Data.List.Split (wordsBy)
import Data.Maybe
import Data.Time.Calendar
import Data.Time.LocalTime
import Safe
import Test.HUnit
#ifdef TESTS
import Test.Framework
import Text.Parsec.Error
#endif
import Text.Parsec hiding (parse)
import Text.Printf
import System.FilePath
import System.Time (getClockTime)

import Hledger.Data
import Hledger.Utils


--- * reader

reader :: Reader
reader = Reader format detect parse

format :: String
format = "journal"

-- | Does the given file path and data look like it might be hledger's journal format ?
detect :: FilePath -> String -> Bool
detect f s
  | f /= "-"  = takeExtension f `elem` ['.':format, ".j"] -- from a known file name: yes if the extension is this format's name or .j
  | otherwise = regexMatches "(^|\n)[0-9]+.*\n[ \t]+" s   -- from stdin: yes if we can see something that looks like a journal entry (digits in column 0 with the next line indented)

-- | Parse and post-process a "Journal" from hledger's journal file
-- format, or give an error.
parse :: Maybe FilePath -> Bool -> FilePath -> String -> ExceptT String IO Journal
parse _ = parseAndFinaliseJournal journalp

--- * parsing utils

-- | A parser of strings with generic user state, monad and return type.
type StringParser u m a = ParsecT String u m a

-- | A string parser with journal-parsing state.
type JournalParser m a = StringParser JournalContext m a

-- | A journal parser that runs in IO and can throw an error mid-parse.
type ErroringJournalParser a = JournalParser (ExceptT String IO) a

-- | Run a string parser with no state in the identity monad.
runStringParser, rsp :: StringParser () Identity a -> String -> Either ParseError a
runStringParser p s = runIdentity $ runParserT p () "" s
rsp = runStringParser

-- | Run a journal parser with a null journal-parsing state.
runJournalParser, rjp :: Monad m => JournalParser m a -> String -> m (Either ParseError a)
runJournalParser p s = runParserT p nullctx "" s
rjp = runJournalParser

-- | Run an error-raising journal parser with a null journal-parsing state.
runErroringJournalParser, rejp :: ErroringJournalParser a -> String -> IO (Either String a)
runErroringJournalParser p s = runExceptT $ runJournalParser p s >>= either (throwError.show) return
rejp = runErroringJournalParser

genericSourcePos :: SourcePos -> GenericSourcePos
genericSourcePos p = GenericSourcePos (sourceName p) (sourceLine p) (sourceColumn p)

-- | Flatten a list of JournalUpdate's (journal-transforming
-- monadic actions which can do IO or raise an exception) into a
-- single equivalent action.
combineJournalUpdates :: [JournalUpdate] -> JournalUpdate
combineJournalUpdates us = foldl' (flip (.)) id <$> sequence us
-- XXX may be contributing to excessive stack use

-- cf http://neilmitchell.blogspot.co.uk/2015/09/detecting-space-leaks.html
-- $ ./devprof +RTS -K576K -xc
-- Exception (reporting due to +RTS -xc): (THUNK_STATIC), stack trace:
--   Hledger.Read.JournalReader.combineJournalUpdates.\,
--   called from Hledger.Read.JournalReader.combineJournalUpdates,
--   called from Hledger.Read.JournalReader.fixedlotprice,
--   called from Hledger.Read.JournalReader.partialbalanceassertion,
--   called from Hledger.Read.JournalReader.getDefaultCommodityAndStyle,
--   called from Hledger.Read.JournalReader.priceamount,
--   called from Hledger.Read.JournalReader.nosymbolamount,
--   called from Hledger.Read.JournalReader.numberp,
--   called from Hledger.Read.JournalReader.rightsymbolamount,
--   called from Hledger.Read.JournalReader.simplecommoditysymbol,
--   called from Hledger.Read.JournalReader.quotedcommoditysymbol,
--   called from Hledger.Read.JournalReader.commoditysymbol,
--   called from Hledger.Read.JournalReader.signp,
--   called from Hledger.Read.JournalReader.leftsymbolamount,
--   called from Hledger.Read.JournalReader.amountp,
--   called from Hledger.Read.JournalReader.spaceandamountormissing,
--   called from Hledger.Read.JournalReader.accountnamep.singlespace,
--   called from Hledger.Utils.Parse.nonspace,
--   called from Hledger.Read.JournalReader.accountnamep,
--   called from Hledger.Read.JournalReader.getAccountAliases,
--   called from Hledger.Read.JournalReader.getParentAccount,
--   called from Hledger.Read.JournalReader.modifiedaccountnamep,
--   called from Hledger.Read.JournalReader.postingp,
--   called from Hledger.Read.JournalReader.postings,
--   called from Hledger.Read.JournalReader.commentStartingWith,
--   called from Hledger.Read.JournalReader.semicoloncomment,
--   called from Hledger.Read.JournalReader.followingcommentp,
--   called from Hledger.Read.JournalReader.descriptionp,
--   called from Hledger.Read.JournalReader.codep,
--   called from Hledger.Read.JournalReader.statusp,
--   called from Hledger.Utils.Parse.spacenonewline,
--   called from Hledger.Read.JournalReader.secondarydatep,
--   called from Hledger.Data.Dates.datesepchar,
--   called from Hledger.Read.JournalReader.datep,
--   called from Hledger.Read.JournalReader.transaction,
--   called from Hledger.Utils.Parse.choice',
--   called from Hledger.Read.JournalReader.directive,
--   called from Hledger.Read.JournalReader.emptyorcommentlinep,
--   called from Hledger.Read.JournalReader.multilinecommentp,
--   called from Hledger.Read.JournalReader.journal.journalItem,
--   called from Hledger.Read.JournalReader.journal,
--   called from Hledger.Read.JournalReader.parseJournalWith,
--   called from Hledger.Read.readJournal.tryReaders.firstSuccessOrBestError,
--   called from Hledger.Read.readJournal.tryReaders,
--   called from Hledger.Read.readJournal,
--   called from Main.main,
--   called from Main.CAF
-- Stack space overflow: current size 33568 bytes.

-- | Given a JournalUpdate-generating parsec parser, file path and data string,
-- parse and post-process a Journal so that it's ready to use, or give an error.
parseAndFinaliseJournal ::
  (ErroringJournalParser (JournalUpdate,JournalContext))
  -> Bool -> FilePath -> String -> ExceptT String IO Journal
parseAndFinaliseJournal parser assrt f s = do
  tc <- liftIO getClockTime
  tl <- liftIO getCurrentLocalTime
  y <- liftIO getCurrentYear
  r <- runParserT parser nullctx{ctxYear=Just y} f s
  case r of
    Right (updates,ctx) -> do
                           j <- ap updates (return nulljournal)
                           case journalFinalise tc tl f s ctx assrt j of
                             Right j'  -> return j'
                             Left estr -> throwError estr
    Left e -> throwError $ show e

setYear :: Monad m => Integer -> JournalParser m ()
setYear y = modifyState (\ctx -> ctx{ctxYear=Just y})

getYear :: Monad m => JournalParser m (Maybe Integer)
getYear = liftM ctxYear getState

setDefaultCommodityAndStyle :: Monad m => (Commodity,AmountStyle) -> JournalParser m ()
setDefaultCommodityAndStyle cs = modifyState (\ctx -> ctx{ctxDefaultCommodityAndStyle=Just cs})

getDefaultCommodityAndStyle :: Monad m => JournalParser m (Maybe (Commodity,AmountStyle))
getDefaultCommodityAndStyle = ctxDefaultCommodityAndStyle `fmap` getState

pushAccount :: Monad m => String -> JournalParser m ()
pushAccount acct = modifyState addAccount
    where addAccount ctx0 = ctx0 { ctxAccounts = acct : ctxAccounts ctx0 }

pushParentAccount :: Monad m => String -> JournalParser m ()
pushParentAccount parent = modifyState addParentAccount
    where addParentAccount ctx0 = ctx0 { ctxParentAccount = parent : ctxParentAccount ctx0 }

popParentAccount :: Monad m => JournalParser m ()
popParentAccount = do ctx0 <- getState
                      case ctxParentAccount ctx0 of
                        [] -> unexpected "End of apply account block with no beginning"
                        (_:rest) -> setState $ ctx0 { ctxParentAccount = rest }

getParentAccount :: Monad m => JournalParser m String
getParentAccount = liftM (concatAccountNames . reverse . ctxParentAccount) getState

addAccountAlias :: Monad m => AccountAlias -> JournalParser m ()
addAccountAlias a = modifyState (\(ctx@Ctx{..}) -> ctx{ctxAliases=a:ctxAliases})

getAccountAliases :: Monad m => JournalParser m [AccountAlias]
getAccountAliases = liftM ctxAliases getState

clearAccountAliases :: Monad m => JournalParser m ()
clearAccountAliases = modifyState (\(ctx@Ctx{..}) -> ctx{ctxAliases=[]})

getIndex :: Monad m => JournalParser m Integer
getIndex = liftM ctxTransactionIndex getState

setIndex :: Monad m => Integer -> JournalParser m ()
setIndex i = modifyState (\ctx -> ctx{ctxTransactionIndex=i})

--- * parsers
--- ** journal

-- | Top-level journal parser. Returns a single composite, I/O performing,
-- error-raising "JournalUpdate" (and final "JournalContext") which can be
-- applied to an empty journal to get the final result.
journalp :: ErroringJournalParser (JournalUpdate,JournalContext)
journalp = do
  journalupdates <- many journalItem
  eof
  finalctx <- getState
  return $ (combineJournalUpdates journalupdates, finalctx)
    where
      -- As all journal line types can be distinguished by the first
      -- character, excepting transactions versus empty (blank or
      -- comment-only) lines, can use choice w/o try
      journalItem = choice [ directivep
                           , liftM (return . addTransaction) transactionp
                           , liftM (return . addModifierTransaction) modifiertransactionp
                           , liftM (return . addPeriodicTransaction) periodictransactionp
                           , liftM (return . addMarketPrice) marketpricedirectivep
                           , emptyorcommentlinep >> return (return id)
                           , multilinecommentp >> return (return id)
                           ] <?> "journal transaction or directive"

--- ** directives

-- cf http://ledger-cli.org/3.0/doc/ledger3.html#Command-Directives
directivep :: ErroringJournalParser JournalUpdate
directivep = do
  optional $ char '!'
  choice' [
    includedirectivep
   ,aliasdirectivep
   ,endaliasesdirectivep
   ,accountdirectivep
   ,applyaccountdirectivep
   ,endapplyaccountdirectivep
   ,tagdirectivep
   ,endtagdirectivep
   ,defaultyeardirectivep
   ,defaultcommoditydirectivep
   ,commodityconversiondirectivep
   ,ignoredpricecommoditydirectivep
   ]
  <?> "directive"

includedirectivep :: ErroringJournalParser JournalUpdate
includedirectivep = do
  string "include"
  many1 spacenonewline
  filename <- restofline
  outerState <- getState
  outerPos <- getPosition
  let curdir = takeDirectory (sourceName outerPos)
  let (u::ExceptT String IO (Journal -> Journal, JournalContext)) = do
       filepath <- expandPath curdir filename
       txt <- readFileOrError outerPos filepath
       let inIncluded = show outerPos ++ " in included file " ++ show filename ++ ":\n"
       r <- runParserT journalp outerState filepath txt

       case r of
         Right (ju, ctx) -> do
                            u <- combineJournalUpdates [ return $ journalAddFile (filepath,txt)
                                                       , ju
                                                       ] `catchError` (throwError . (inIncluded ++))
                            return (u, ctx)
         Left err -> throwError $ inIncluded ++ show err
       where readFileOrError pos fp =
                ExceptT $ liftM Right (readFile' fp) `C.catch`
                  \e -> return $ Left $ printf "%s reading %s:\n%s" (show pos) fp (show (e::C.IOException))
  r <- liftIO $ runExceptT u
  case r of
    Left err -> return $ throwError err
    Right (ju, _finalparsectx) -> return $ ExceptT $ return $ Right ju

journalAddFile :: (FilePath,String) -> Journal -> Journal
journalAddFile f j@Journal{files=fs} = j{files=fs++[f]}
 -- NOTE: first encountered file to left, to avoid a reverse

accountdirectivep :: ErroringJournalParser JournalUpdate
accountdirectivep = do
  string "account"
  many1 spacenonewline
  acct <- accountnamep
  newline
  let indentedline = many1 spacenonewline >> restofline
  many indentedline
  pushAccount acct
  return $ ExceptT $ return $ Right id

applyaccountdirectivep :: ErroringJournalParser JournalUpdate
applyaccountdirectivep = do
  string "apply" >> many1 spacenonewline >> string "account"
  many1 spacenonewline
  parent <- accountnamep
  newline
  pushParentAccount parent
  return $ ExceptT $ return $ Right id

endapplyaccountdirectivep :: ErroringJournalParser JournalUpdate
endapplyaccountdirectivep = do
  string "end" >> many1 spacenonewline >> string "apply" >> many1 spacenonewline >> string "account"
  popParentAccount
  return $ ExceptT $ return $ Right id

aliasdirectivep :: ErroringJournalParser JournalUpdate
aliasdirectivep = do
  string "alias"
  many1 spacenonewline
  alias <- accountaliasp
  addAccountAlias alias
  return $ return id

accountaliasp :: Monad m => StringParser u m AccountAlias
accountaliasp = regexaliasp <|> basicaliasp

basicaliasp :: Monad m => StringParser u m AccountAlias
basicaliasp = do
  -- pdbg 0 "basicaliasp"
  old <- rstrip <$> (many1 $ noneOf "=")
  char '='
  many spacenonewline
  new <- rstrip <$> anyChar `manyTill` eolof  -- don't require a final newline, good for cli options
  return $ BasicAlias old new

regexaliasp :: Monad m => StringParser u m AccountAlias
regexaliasp = do
  -- pdbg 0 "regexaliasp"
  char '/'
  re <- many1 $ noneOf "/\n\r" -- paranoid: don't try to read past line end
  char '/'
  many spacenonewline
  char '='
  many spacenonewline
  repl <- rstrip <$> anyChar `manyTill` eolof
  return $ RegexAlias re repl

endaliasesdirectivep :: ErroringJournalParser JournalUpdate
endaliasesdirectivep = do
  string "end aliases"
  clearAccountAliases
  return (return id)

tagdirectivep :: ErroringJournalParser JournalUpdate
tagdirectivep = do
  string "tag" <?> "tag directive"
  many1 spacenonewline
  _ <- many1 nonspace
  restofline
  return $ return id

endtagdirectivep :: ErroringJournalParser JournalUpdate
endtagdirectivep = do
  (string "end tag" <|> string "pop") <?> "end tag or pop directive"
  restofline
  return $ return id

defaultyeardirectivep :: ErroringJournalParser JournalUpdate
defaultyeardirectivep = do
  char 'Y' <?> "default year"
  many spacenonewline
  y <- many1 digit
  let y' = read y
  failIfInvalidYear y
  setYear y'
  return $ return id

defaultcommoditydirectivep :: ErroringJournalParser JournalUpdate
defaultcommoditydirectivep = do
  char 'D' <?> "default commodity"
  many1 spacenonewline
  Amount{..} <- amountp
  setDefaultCommodityAndStyle (acommodity, astyle)
  restofline
  return $ return id

marketpricedirectivep :: ErroringJournalParser MarketPrice
marketpricedirectivep = do
  char 'P' <?> "market price"
  many spacenonewline
  date <- try (do {LocalTime d _ <- datetimep; return d}) <|> datep -- a time is ignored
  many1 spacenonewline
  symbol <- commoditysymbolp
  many spacenonewline
  price <- amountp
  restofline
  return $ MarketPrice date symbol price

ignoredpricecommoditydirectivep :: ErroringJournalParser JournalUpdate
ignoredpricecommoditydirectivep = do
  char 'N' <?> "ignored-price commodity"
  many1 spacenonewline
  commoditysymbolp
  restofline
  return $ return id

commodityconversiondirectivep :: ErroringJournalParser JournalUpdate
commodityconversiondirectivep = do
  char 'C' <?> "commodity conversion"
  many1 spacenonewline
  amountp
  many spacenonewline
  char '='
  many spacenonewline
  amountp
  restofline
  return $ return id

--- ** transactions

modifiertransactionp :: ErroringJournalParser ModifierTransaction
modifiertransactionp = do
  char '=' <?> "modifier transaction"
  many spacenonewline
  valueexpr <- restofline
  postings <- postingsp Nothing
  return $ ModifierTransaction valueexpr postings

periodictransactionp :: ErroringJournalParser PeriodicTransaction
periodictransactionp = do
  char '~' <?> "periodic transaction"
  many spacenonewline
  periodexpr <- restofline
  postings <- postingsp Nothing
  return $ PeriodicTransaction periodexpr postings

-- | Parse a (possibly unbalanced) transaction.
transactionp :: ErroringJournalParser Transaction
transactionp = do
  -- ptrace "transactionp"
  sourcepos <- genericSourcePos <$> getPosition
  date <- datep <?> "transaction"
  edate <- optionMaybe (secondarydatep date) <?> "secondary date"
  lookAhead (spacenonewline <|> newline) <?> "whitespace or newline"
  status <- statusp <?> "cleared status"
  code <- codep <?> "transaction code"
  description <- descriptionp >>= return . strip
  comment <- try followingcommentp <|> (newline >> return "")
  let tags = commentTags comment
  postings <- postingsp (Just date)
  i' <- (+1) <$> getIndex
  setIndex i'
  return $ txnTieKnot $ Transaction i' sourcepos date edate status code description comment tags postings ""

#ifdef TESTS
test_transactionp = do
    let s `gives` t = do
                        let p = parseWithCtx nullctx transactionp s
                        assertBool $ isRight p
                        let Right t2 = p
                            -- same f = assertEqual (f t) (f t2)
                        assertEqual (tdate t) (tdate t2)
                        assertEqual (tdate2 t) (tdate2 t2)
                        assertEqual (tstatus t) (tstatus t2)
                        assertEqual (tcode t) (tcode t2)
                        assertEqual (tdescription t) (tdescription t2)
                        assertEqual (tcomment t) (tcomment t2)
                        assertEqual (ttags t) (ttags t2)
                        assertEqual (tpreceding_comment_lines t) (tpreceding_comment_lines t2)
                        assertEqual (show $ tpostings t) (show $ tpostings t2)
    -- "0000/01/01\n\n" `gives` nulltransaction
    unlines [
      "2012/05/14=2012/05/15 (code) desc  ; tcomment1",
      "    ; tcomment2",
      "    ; ttag1: val1",
      "    * a         $1.00  ; pcomment1",
      "    ; pcomment2",
      "    ; ptag1: val1",
      "    ; ptag2: val2"
      ]
     `gives`
     nulltransaction{
      tdate=parsedate "2012/05/14",
      tdate2=Just $ parsedate "2012/05/15",
      tstatus=Uncleared,
      tcode="code",
      tdescription="desc",
      tcomment=" tcomment1\n tcomment2\n ttag1: val1\n",
      ttags=[("ttag1","val1")],
      tpostings=[
        nullposting{
          pstatus=Cleared,
          paccount="a",
          pamount=Mixed [usd 1],
          pcomment=" pcomment1\n pcomment2\n ptag1: val1\n  ptag2: val2\n",
          ptype=RegularPosting,
          ptags=[("ptag1","val1"),("ptag2","val2")],
          ptransaction=Nothing
          }
        ],
      tpreceding_comment_lines=""
      }
    unlines [
      "2015/1/1",
      ]
     `gives`
     nulltransaction{
      tdate=parsedate "2015/01/01",
      }

    assertRight $ parseWithCtx nullctx transactionp $ unlines
      ["2007/01/28 coopportunity"
      ,"    expenses:food:groceries                   $47.18"
      ,"    assets:checking                          $-47.18"
      ,""
      ]

    -- transactionp should not parse just a date
    assertLeft $ parseWithCtx nullctx transactionp "2009/1/1\n"

    -- transactionp should not parse just a date and description
    assertLeft $ parseWithCtx nullctx transactionp "2009/1/1 a\n"

    -- transactionp should not parse a following comment as part of the description
    let p = parseWithCtx nullctx transactionp "2009/1/1 a ;comment\n b 1\n"
    assertRight p
    assertEqual "a" (let Right p' = p in tdescription p')

    -- parse transaction with following whitespace line
    assertRight $ parseWithCtx nullctx transactionp $ unlines
        ["2012/1/1"
        ,"  a  1"
        ,"  b"
        ," "
        ]

    let p = parseWithCtx nullctx transactionp $ unlines
             ["2009/1/1 x  ; transaction comment"
             ," a  1  ; posting 1 comment"
             ," ; posting 1 comment 2"
             ," b"
             ," ; posting 2 comment"
             ]
    assertRight p
    assertEqual 2 (let Right t = p in length $ tpostings t)
#endif

statusp :: Monad m => JournalParser m ClearedStatus
statusp =
  choice'
    [ many spacenonewline >> char '*' >> return Cleared
    , many spacenonewline >> char '!' >> return Pending
    , return Uncleared
    ]
    <?> "cleared status"

codep :: Monad m => JournalParser m String
codep = try (do { many1 spacenonewline; char '(' <?> "codep"; code <- anyChar `manyTill` char ')'; return code } ) <|> return ""

descriptionp = many (noneOf ";\n")

--- ** dates

-- | Parse a date in YYYY/MM/DD format.
-- Hyphen (-) and period (.) are also allowed as separators.
-- The year may be omitted if a default year has been set.
-- Leading zeroes may be omitted.
datep :: Monad m => JournalParser m Day
datep = do
  -- hacky: try to ensure precise errors for invalid dates
  -- XXX reported error position is not too good
  -- pos <- genericSourcePos <$> getPosition
  datestr <- do
    c <- digit
    cs <- many $ choice' [digit, datesepchar]
    return $ c:cs
  let sepchars = nub $ sort $ filter (`elem` datesepchars) datestr
  when (length sepchars /= 1) $ fail $ "bad date, different separators used: " ++ datestr
  let dateparts = wordsBy (`elem` datesepchars) datestr
  currentyear <- getYear
  [y,m,d] <- case (dateparts,currentyear) of
              ([m,d],Just y)  -> return [show y,m,d]
              ([_,_],Nothing) -> fail $ "partial date "++datestr++" found, but the current year is unknown"
              ([y,m,d],_)     -> return [y,m,d]
              _               -> fail $ "bad date: " ++ datestr
  let maybedate = fromGregorianValid (read y) (read m) (read d)
  case maybedate of
    Nothing   -> fail $ "bad date: " ++ datestr
    Just date -> return date
  <?> "full or partial date"

-- | Parse a date and time in YYYY/MM/DD HH:MM[:SS][+-ZZZZ] format.
-- Hyphen (-) and period (.) are also allowed as date separators.
-- The year may be omitted if a default year has been set.
-- Seconds are optional.
-- The timezone is optional and ignored (the time is always interpreted as a local time).
-- Leading zeroes may be omitted (except in a timezone).
datetimep :: Monad m => JournalParser m LocalTime
datetimep = do
  day <- datep
  many1 spacenonewline
  h <- many1 digit
  let h' = read h
  guard $ h' >= 0 && h' <= 23
  char ':'
  m <- many1 digit
  let m' = read m
  guard $ m' >= 0 && m' <= 59
  s <- optionMaybe $ char ':' >> many1 digit
  let s' = case s of Just sstr -> read sstr
                     Nothing   -> 0
  guard $ s' >= 0 && s' <= 59
  {- tz <- -}
  optionMaybe $ do
                   plusminus <- oneOf "-+"
                   d1 <- digit
                   d2 <- digit
                   d3 <- digit
                   d4 <- digit
                   return $ plusminus:d1:d2:d3:d4:""
  -- ltz <- liftIO $ getCurrentTimeZone
  -- let tz' = maybe ltz (fromMaybe ltz . parseTime defaultTimeLocale "%z") tz
  -- return $ localTimeToUTC tz' $ LocalTime day $ TimeOfDay h' m' (fromIntegral s')
  return $ LocalTime day $ TimeOfDay h' m' (fromIntegral s')

secondarydatep :: Monad m => Day -> JournalParser m Day
secondarydatep primarydate = do
  char '='
  -- kludgy way to use primary date for default year
  let withDefaultYear d p = do
        y <- getYear
        let (y',_,_) = toGregorian d in setYear y'
        r <- p
        when (isJust y) $ setYear $ fromJust y
        return r
  edate <- withDefaultYear primarydate datep
  return edate

-- |
-- >> parsewith twoorthreepartdatestringp "2016/01/2"
-- Right "2016/01/2"
-- twoorthreepartdatestringp = do
--   n1 <- many1 digit
--   c <- datesepchar
--   n2 <- many1 digit
--   mn3 <- optionMaybe $ char c >> many1 digit
--   return $ n1 ++ c:n2 ++ maybe "" (c:) mn3

--- ** postings

-- Parse the following whitespace-beginning lines as postings, posting
-- tags, and/or comments (inferring year, if needed, from the given date).
postingsp :: Maybe Day -> ErroringJournalParser [Posting]
postingsp mdate = many (try $ postingp mdate) <?> "postings"

-- linebeginningwithspaces :: Monad m => JournalParser m String
-- linebeginningwithspaces = do
--   sp <- many1 spacenonewline
--   c <- nonspace
--   cs <- restofline
--   return $ sp ++ (c:cs) ++ "\n"

postingp :: Maybe Day -> ErroringJournalParser Posting
postingp mtdate = do
  -- pdbg 0 "postingp"
  many1 spacenonewline
  status <- statusp
  many spacenonewline
  account <- modifiedaccountnamep
  let (ptype, account') = (accountNamePostingType account, unbracket account)
  amount <- spaceandamountormissingp
  massertion <- partialbalanceassertionp
  _ <- fixedlotpricep
  many spacenonewline
  (comment,tags,mdate,mdate2) <-
    try (followingcommentandtagsp mtdate) <|> (newline >> return ("",[],Nothing,Nothing))
  return posting
   { pdate=mdate
   , pdate2=mdate2
   , pstatus=status
   , paccount=account'
   , pamount=amount
   , pcomment=comment
   , ptype=ptype
   , ptags=tags
   , pbalanceassertion=massertion
   }

#ifdef TESTS
test_postingp = do
    let s `gives` ep = do
                         let parse = parseWithCtx nullctx (postingp Nothing) s
                         assertBool -- "postingp parser"
                           $ isRight parse
                         let Right ap = parse
                             same f = assertEqual (f ep) (f ap)
                         same pdate
                         same pstatus
                         same paccount
                         same pamount
                         same pcomment
                         same ptype
                         same ptags
                         same ptransaction
    "  expenses:food:dining  $10.00   ; a: a a \n   ; b: b b \n" `gives`
      posting{paccount="expenses:food:dining", pamount=Mixed [usd 10], pcomment=" a: a a \n b: b b \n", ptags=[("a","a a"), ("b","b b")]}

    " a  1 ; [2012/11/28]\n" `gives`
      ("a" `post` num 1){pcomment=" [2012/11/28]\n"
                        ,ptags=[("date","2012/11/28")]
                        ,pdate=parsedateM "2012/11/28"}

    " a  1 ; a:a, [=2012/11/28]\n" `gives`
      ("a" `post` num 1){pcomment=" a:a, [=2012/11/28]\n"
                        ,ptags=[("a","a"), ("date2","2012/11/28")]
                        ,pdate=Nothing}

    " a  1 ; a:a\n  ; [2012/11/28=2012/11/29],b:b\n" `gives`
      ("a" `post` num 1){pcomment=" a:a\n [2012/11/28=2012/11/29],b:b\n"
                        ,ptags=[("a","a"), ("date","2012/11/28"), ("date2","2012/11/29"), ("b","b")]
                        ,pdate=parsedateM "2012/11/28"}

    assertBool -- "postingp parses a quoted commodity with numbers"
      (isRight $ parseWithCtx nullctx (postingp Nothing) "  a  1 \"DE123\"\n")

  -- ,"postingp parses balance assertions and fixed lot prices" ~: do
    assertBool (isRight $ parseWithCtx nullctx (postingp Nothing) "  a  1 \"DE123\" =$1 { =2.2 EUR} \n")

    -- let parse = parseWithCtx nullctx postingp " a\n ;next-line comment\n"
    -- assertRight parse
    -- let Right p = parse
    -- assertEqual "next-line comment\n" (pcomment p)
    -- assertEqual (Just nullmixedamt) (pbalanceassertion p)
#endif

--- ** account names

-- | Parse an account name, then apply any parent account prefix and/or account aliases currently in effect.
modifiedaccountnamep :: Monad m => JournalParser m AccountName
modifiedaccountnamep = do
  parent <- getParentAccount
  aliases <- getAccountAliases
  a <- accountnamep
  return $
    accountNameApplyAliases aliases $
     -- XXX accountNameApplyAliasesMemo ? doesn't seem to make a difference
    joinAccountNames parent
    a

-- | Parse an account name. Account names start with a non-space, may
-- have single spaces inside them, and are terminated by two or more
-- spaces (or end of input). Also they have one or more components of
-- at least one character, separated by the account separator char.
-- (This parser will also consume one following space, if present.)
accountnamep :: Monad m => StringParser u m AccountName
accountnamep = do
    a <- do
      c <- nonspace
      cs <- striptrailingspace <$> many (nonspace <|> singlespace)
      return $ c:cs
    when (accountNameFromComponents (accountNameComponents a) /= a)
         (fail $ "account name seems ill-formed: "++a)
    return a
    where
      singlespace = try (do {spacenonewline; do {notFollowedBy spacenonewline; return ' '}})
      striptrailingspace "" = ""
      striptrailingspace s  = if last s == ' ' then init s else s

-- accountnamechar = notFollowedBy (oneOf "()[]") >> nonspace
--     <?> "account name character (non-bracket, non-parenthesis, non-whitespace)"

--- ** amounts

-- | Parse whitespace then an amount, with an optional left or right
-- currency symbol and optional price, or return the special
-- "missing" marker amount.
spaceandamountormissingp :: Monad m => JournalParser m MixedAmount
spaceandamountormissingp =
  try (do
        many1 spacenonewline
        (Mixed . (:[])) `fmap` amountp <|> return missingmixedamt
      ) <|> return missingmixedamt

#ifdef TESTS
assertParseEqual' :: (Show a, Eq a) => (Either ParseError a) -> a -> Assertion
assertParseEqual' parse expected = either (assertFailure.show) (`is'` expected) parse

is' :: (Eq a, Show a) => a -> a -> Assertion
a `is'` e = assertEqual e a

test_spaceandamountormissingp = do
    assertParseEqual' (parseWithCtx nullctx spaceandamountormissingp " $47.18") (Mixed [usd 47.18])
    assertParseEqual' (parseWithCtx nullctx spaceandamountormissingp "$47.18") missingmixedamt
    assertParseEqual' (parseWithCtx nullctx spaceandamountormissingp " ") missingmixedamt
    assertParseEqual' (parseWithCtx nullctx spaceandamountormissingp "") missingmixedamt
#endif

-- | Parse a single-commodity amount, with optional symbol on the left or
-- right, optional unit or total price, and optional (ignored)
-- ledger-style balance assertion or fixed lot price declaration.
amountp :: Monad m => JournalParser m Amount
amountp = try leftsymbolamountp <|> try rightsymbolamountp <|> nosymbolamountp

#ifdef TESTS
test_amountp = do
    assertParseEqual' (parseWithCtx nullctx amountp "$47.18") (usd 47.18)
    assertParseEqual' (parseWithCtx nullctx amountp "$1.") (usd 1 `withPrecision` 0)
  -- ,"amount with unit price" ~: do
    assertParseEqual'
     (parseWithCtx nullctx amountp "$10 @ €0.5")
     (usd 10 `withPrecision` 0 `at` (eur 0.5 `withPrecision` 1))
  -- ,"amount with total price" ~: do
    assertParseEqual'
     (parseWithCtx nullctx amountp "$10 @@ €5")
     (usd 10 `withPrecision` 0 @@ (eur 5 `withPrecision` 0))
#endif

-- | Parse an amount from a string, or get an error.
amountp' :: String -> Amount
amountp' s =
  case runParser (amountp <* eof) nullctx "" s of
    Right t -> t
    Left err -> error' $ show err -- XXX should throwError

-- | Parse a mixed amount from a string, or get an error.
mamountp' :: String -> MixedAmount
mamountp' = Mixed . (:[]) . amountp'

signp :: Monad m => JournalParser m String
signp = do
  sign <- optionMaybe $ oneOf "+-"
  return $ case sign of Just '-' -> "-"
                        _        -> ""

leftsymbolamountp :: Monad m => JournalParser m Amount
leftsymbolamountp = do
  sign <- signp
  c <- commoditysymbolp
  sp <- many spacenonewline
  (q,prec,mdec,mgrps) <- numberp
  let s = amountstyle{ascommodityside=L, ascommodityspaced=not $ null sp, asprecision=prec, asdecimalpoint=mdec, asdigitgroups=mgrps}
  p <- priceamountp
  let applysign = if sign=="-" then negate else id
  return $ applysign $ Amount c q p s
  <?> "left-symbol amount"

rightsymbolamountp :: Monad m => JournalParser m Amount
rightsymbolamountp = do
  (q,prec,mdec,mgrps) <- numberp
  sp <- many spacenonewline
  c <- commoditysymbolp
  p <- priceamountp
  let s = amountstyle{ascommodityside=R, ascommodityspaced=not $ null sp, asprecision=prec, asdecimalpoint=mdec, asdigitgroups=mgrps}
  return $ Amount c q p s
  <?> "right-symbol amount"

nosymbolamountp :: Monad m => JournalParser m Amount
nosymbolamountp = do
  (q,prec,mdec,mgrps) <- numberp
  p <- priceamountp
  -- apply the most recently seen default commodity and style to this commodityless amount
  defcs <- getDefaultCommodityAndStyle
  let (c,s) = case defcs of
        Just (defc,defs) -> (defc, defs{asprecision=max (asprecision defs) prec})
        Nothing          -> ("", amountstyle{asprecision=prec, asdecimalpoint=mdec, asdigitgroups=mgrps})
  return $ Amount c q p s
  <?> "no-symbol amount"

commoditysymbolp :: Monad m => JournalParser m String
commoditysymbolp = (quotedcommoditysymbolp <|> simplecommoditysymbolp) <?> "commodity symbol"

quotedcommoditysymbolp :: Monad m => JournalParser m String
quotedcommoditysymbolp = do
  char '"'
  s <- many1 $ noneOf ";\n\""
  char '"'
  return s

simplecommoditysymbolp :: Monad m => JournalParser m String
simplecommoditysymbolp = many1 (noneOf nonsimplecommoditychars)

priceamountp :: Monad m => JournalParser m Price
priceamountp =
    try (do
          many spacenonewline
          char '@'
          try (do
                char '@'
                many spacenonewline
                a <- amountp -- XXX can parse more prices ad infinitum, shouldn't
                return $ TotalPrice a)
           <|> (do
            many spacenonewline
            a <- amountp -- XXX can parse more prices ad infinitum, shouldn't
            return $ UnitPrice a))
         <|> return NoPrice

partialbalanceassertionp :: Monad m => JournalParser m (Maybe MixedAmount)
partialbalanceassertionp =
    try (do
          many spacenonewline
          char '='
          many spacenonewline
          a <- amountp -- XXX should restrict to a simple amount
          return $ Just $ Mixed [a])
         <|> return Nothing

-- balanceassertion :: Monad m => JournalParser m (Maybe MixedAmount)
-- balanceassertion =
--     try (do
--           many spacenonewline
--           string "=="
--           many spacenonewline
--           a <- amountp -- XXX should restrict to a simple amount
--           return $ Just $ Mixed [a])
--          <|> return Nothing

-- http://ledger-cli.org/3.0/doc/ledger3.html#Fixing-Lot-Prices
fixedlotpricep :: Monad m => JournalParser m (Maybe Amount)
fixedlotpricep =
    try (do
          many spacenonewline
          char '{'
          many spacenonewline
          char '='
          many spacenonewline
          a <- amountp -- XXX should restrict to a simple amount
          many spacenonewline
          char '}'
          return $ Just a)
         <|> return Nothing

-- | Parse a string representation of a number for its value and display
-- attributes.
--
-- Some international number formats are accepted, eg either period or comma
-- may be used for the decimal point, and the other of these may be used for
-- separating digit groups in the integer part. See
-- http://en.wikipedia.org/wiki/Decimal_separator for more examples.
--
-- This returns: the parsed numeric value, the precision (number of digits
-- seen following the decimal point), the decimal point character used if any,
-- and the digit group style if any.
--
numberp :: Monad m => JournalParser m (Quantity, Int, Maybe Char, Maybe DigitGroupStyle)
numberp = do
  -- a number is an optional sign followed by a sequence of digits possibly
  -- interspersed with periods, commas, or both
  -- ptrace "numberp"
  sign <- signp
  parts <- many1 $ choice' [many1 digit, many1 $ char ',', many1 $ char '.']
  dbg8 "numberp parsed" (sign,parts) `seq` return ()

  -- check the number is well-formed and identify the decimal point and digit
  -- group separator characters used, if any
  let (numparts, puncparts) = partition numeric parts
      (ok, mdecimalpoint, mseparator) =
          case (numparts, puncparts) of
            ([],_)     -> (False, Nothing, Nothing)  -- no digits, not ok
            (_,[])     -> (True, Nothing, Nothing)   -- digits with no punctuation, ok
            (_,[[d]])  -> (True, Just d, Nothing)    -- just a single punctuation of length 1, assume it's a decimal point
            (_,[_])    -> (False, Nothing, Nothing)  -- a single punctuation of some other length, not ok
            (_,_:_:_)  ->                                       -- two or more punctuations
              let (s:ss, d) = (init puncparts, last puncparts)  -- the leftmost is a separator and the rightmost may be a decimal point
              in if (any ((/=1).length) puncparts               -- adjacent punctuation chars, not ok
                     || any (s/=) ss                            -- separator chars vary, not ok
                     || head parts == s)                        -- number begins with a separator char, not ok
                 then (False, Nothing, Nothing)
                 else if s == d
                      then (True, Nothing, Just $ head s)       -- just one kind of punctuation - must be separators
                      else (True, Just $ head d, Just $ head s) -- separator(s) and a decimal point
  when (not ok) (fail $ "number seems ill-formed: "++concat parts)

  -- get the digit group sizes and digit group style if any
  let (intparts',fracparts') = span ((/= mdecimalpoint) . Just . head) parts
      (intparts, fracpart) = (filter numeric intparts', filter numeric fracparts')
      groupsizes = reverse $ case map length intparts of
                               (a:b:cs) | a < b -> b:cs
                               gs               -> gs
      mgrps = maybe Nothing (Just . (`DigitGroups` groupsizes)) $ mseparator

  -- put the parts back together without digit group separators, get the precision and parse the value
  let int = concat $ "":intparts
      frac = concat $ "":fracpart
      precision = length frac
      int' = if null int then "0" else int
      frac' = if null frac then "0" else frac
      quantity = read $ sign++int'++"."++frac' -- this read should never fail

  return $ dbg8 "numberp quantity,precision,mdecimalpoint,mgrps" (quantity,precision,mdecimalpoint,mgrps)
  <?> "numberp"
  where
    numeric = isNumber . headDef '_'

-- test_numberp = do
--       let s `is` n = assertParseEqual (parseWithCtx nullctx numberp s) n
--           assertFails = assertBool . isLeft . parseWithCtx nullctx numberp
--       assertFails ""
--       "0"          `is` (0, 0, '.', ',', [])
--       "1"          `is` (1, 0, '.', ',', [])
--       "1.1"        `is` (1.1, 1, '.', ',', [])
--       "1,000.1"    `is` (1000.1, 1, '.', ',', [3])
--       "1.00.000,1" `is` (100000.1, 1, ',', '.', [3,2])
--       "1,000,000"  `is` (1000000, 0, '.', ',', [3,3])
--       "1."         `is` (1,   0, '.', ',', [])
--       "1,"         `is` (1,   0, ',', '.', [])
--       ".1"         `is` (0.1, 1, '.', ',', [])
--       ",1"         `is` (0.1, 1, ',', '.', [])
--       assertFails "1,000.000,1"
--       assertFails "1.000,000.1"
--       assertFails "1,000.000.1"
--       assertFails "1,,1"
--       assertFails "1..1"
--       assertFails ".1,"
--       assertFails ",1."

--- ** comments

multilinecommentp :: Monad m => JournalParser m ()
multilinecommentp = do
  string "comment" >> many spacenonewline >> newline
  go
  where
    go = try (eof <|> (string "end comment" >> newline >> return ()))
         <|> (anyLine >> go)
    anyLine = anyChar `manyTill` newline

emptyorcommentlinep :: Monad m => JournalParser m ()
emptyorcommentlinep = do
  many spacenonewline >> (commentp <|> (many spacenonewline >> newline >> return ""))
  return ()

-- | Parse a possibly multi-line comment following a semicolon.
followingcommentp :: Monad m => JournalParser m String
followingcommentp =
  -- ptrace "followingcommentp"
  do samelinecomment <- many spacenonewline >> (try semicoloncommentp <|> (newline >> return ""))
     newlinecomments <- many (try (many1 spacenonewline >> semicoloncommentp))
     return $ unlines $ samelinecomment:newlinecomments

-- | Parse a possibly multi-line comment following a semicolon, and
-- any tags and/or posting dates within it. Posting dates can be
-- expressed with "date"/"date2" tags and/or bracketed dates.  The
-- dates are parsed in full here so that errors are reported in the
-- right position. Missing years can be inferred if a default date is
-- provided.
--
-- >>> rejp (followingcommentandtagsp (Just $ fromGregorian 2000 1 2)) "; a:b, date:3/4, [=5/6]"
-- Right ("a:b, date:3/4, [=5/6]\n",[("a","b"),("date","3/4")],Just 2000-03-04,Just 2000-05-06)
--
-- Year unspecified and no default provided -> unknown year error, at correct position:
-- >>> rejp (followingcommentandtagsp Nothing) "  ;    xxx   date:3/4\n  ; second line"
-- Left ...line 1, column 22...year is unknown...
--
-- Date tag value contains trailing text - forgot the comma, confused:
-- the syntaxes ?  We'll accept the leading date anyway
-- >>> rejp (followingcommentandtagsp (Just $ fromGregorian 2000 1 2)) "; date:3/4=5/6"
-- Right ("date:3/4=5/6\n",[("date","3/4=5/6")],Just 2000-03-04,Nothing)
--
followingcommentandtagsp :: Maybe Day -> ErroringJournalParser (String, [Tag], Maybe Day, Maybe Day)
followingcommentandtagsp mdefdate = do
  -- pdbg 0 "followingcommentandtagsp"

  -- Parse a single or multi-line comment, starting on this line or the next one.
  -- Save the starting position and preserve all whitespace for the subsequent re-parsing,
  -- to get good error positions.
  startpos <- getPosition
  commentandwhitespace <- do
    let semicoloncommentp' = (:) <$> char ';' <*> anyChar `manyTill` eolof
    sp1 <- many spacenonewline
    l1  <- try semicoloncommentp' <|> (newline >> return "")
    ls  <- many $ try ((++) <$> many1 spacenonewline <*> semicoloncommentp')
    return $ unlines $ (sp1 ++ l1) : ls
  let comment = unlines $ map (lstrip . dropWhile (==';') . strip) $ lines commentandwhitespace
  -- pdbg 0 $ "commentws:"++show commentandwhitespace
  -- pdbg 0 $ "comment:"++show comment

  -- Reparse the comment for any tags.
  tags <- case runStringParser (setPosition startpos >> tagsp) commentandwhitespace of
            Right ts -> return ts
            Left e   -> throwError $ show e
  -- pdbg 0 $ "tags: "++show tags

  -- Reparse the comment for any posting dates. Use the transaction date for defaults, if provided.
  epdates <- liftIO $ rejp (setPosition startpos >> postingdatesp mdefdate) commentandwhitespace
  pdates <- case epdates of
              Right ds -> return ds
              Left e   -> throwError e
  -- pdbg 0 $ "pdates: "++show pdates
  let mdate  = headMay $ map snd $ filter ((=="date").fst)  pdates
      mdate2 = headMay $ map snd $ filter ((=="date2").fst) pdates

  return (comment, tags, mdate, mdate2)

commentp :: Monad m => JournalParser m String
commentp = commentStartingWithp commentchars

commentchars :: [Char]
commentchars = "#;*"

semicoloncommentp :: Monad m => JournalParser m String
semicoloncommentp = commentStartingWithp ";"

commentStartingWithp :: Monad m => String -> JournalParser m String
commentStartingWithp cs = do
  -- ptrace "commentStartingWith"
  oneOf cs
  many spacenonewline
  l <- anyChar `manyTill` eolof
  optional newline
  return l

--- ** tags

-- | Extract any tags (name:value ended by comma or newline) embedded in a string.
--
-- >>> commentTags "a b:, c:c d:d, e"
-- [("b",""),("c","c d:d")]
--
-- >>> commentTags "a [1/1/1] [1/1] [1], [=1/1/1] [=1/1] [=1] [1/1=1/1/1] [1=1/1/1] b:c"
-- [("b","c")]
--
-- --[("date","1/1/1"),("date","1/1"),("date2","1/1/1"),("date2","1/1"),("date","1/1"),("date2","1/1/1"),("date","1"),("date2","1/1/1")]
--
-- >>> commentTags "\na b:, \nd:e, f"
-- [("b",""),("d","e")]
--
commentTags :: String -> [Tag]
commentTags s =
  case runStringParser tagsp s of
    Right r -> r
    Left _  -> [] -- shouldn't happen

-- | Parse all tags found in a string.
tagsp :: StringParser u Identity [Tag]
tagsp = do
  -- pdbg 0 $ "tagsp"
  many (try (nontagp >> tagp))

-- | Parse everything up till the first tag.
--
-- >>> rsp nontagp "\na b:, \nd:e, f"
-- Right "\na "
nontagp :: StringParser u Identity String
nontagp = do
  -- pdbg 0 "nontagp"
  -- anyChar `manyTill` (lookAhead (try (tagorbracketeddatetagsp Nothing >> return ()) <|> eof))
  anyChar `manyTill` (lookAhead (try (tagp >> return ()) <|> eof))
  -- XXX costly ?

-- | Tags begin with a colon-suffixed tag name (a word beginning with
-- a letter) and are followed by a tag value (any text up to a comma
-- or newline, whitespace-stripped).
--
-- >>> rsp tagp "a:b b , c AuxDate: 4/2"
-- Right ("a","b b")
--
tagp :: Monad m => StringParser u m Tag
tagp = do
  -- pdbg 0 "tagp"
  n <- tagnamep
  v <- tagvaluep
  return (n,v)

-- |
-- >>> rsp tagnamep "a:"
-- Right "a"
tagnamep :: Monad m => StringParser u m String
tagnamep = do
  -- pdbg 0 "tagnamep"
  many1 (noneOf ": \t\n") <* char ':'

tagvaluep :: Monad m => StringParser u m String
tagvaluep = do
  -- ptrace "tagvalue"
  v <- anyChar `manyTill` ((try (char ',') >> return ()) <|> eolof)
  return $ strip $ reverse $ dropWhile (==',') $ reverse $ strip v

--- ** posting dates

-- | Parse all posting dates found in a string. Posting dates can be
-- expressed with date/date2 tags and/or bracketed dates.  The dates
-- are parsed fully to give useful errors. Missing years can be
-- inferred only if a default date is provided.
--
postingdatesp :: Maybe Day -> ErroringJournalParser [(TagName,Day)]
postingdatesp mdefdate = do
  -- pdbg 0 $ "postingdatesp"
  let p = (datetagp mdefdate >>= return.(:[])) <|> bracketeddatetagsp mdefdate
      nonp =
         many (notFollowedBy p >> anyChar)
         -- anyChar `manyTill` (lookAhead (try (p >> return ()) <|> eof))
  concat <$> (many $ try (nonp >> p))

--- ** date tags

-- | Date tags are tags with name "date" or "date2". Their value is
-- parsed as a date, using the provided default date if any for
-- inferring a missing year if needed. Any error in date parsing is
-- reported and terminates parsing.
--
-- >>> rejp (datetagp Nothing) "date: 2000/1/2 "
-- Right ("date",2000-01-02)
--
-- >>> rejp (datetagp (Just $ fromGregorian 2001 2 3)) "date2:3/4"
-- Right ("date2",2001-03-04)
--
-- >>> rejp (datetagp Nothing) "date:  3/4"
-- Left ...line 1, column 9...year is unknown...
--
datetagp :: Maybe Day -> ErroringJournalParser (TagName,Day)
datetagp mdefdate = do
  -- pdbg 0 "datetagp"
  string "date"
  n <- maybe "" id <$> optionMaybe (string "2")
  char ':'
  startpos <- getPosition
  v <- tagvaluep
  -- re-parse value as a date.
  ctx <- getState
  ep <- parseWithCtx
    ctx{ctxYear=first3.toGregorian <$> mdefdate}
    -- The value extends to a comma, newline, or end of file.
    -- It seems like ignoring any extra stuff following a date
    -- gives better errors here.
    (do
        setPosition startpos
        datep) -- <* eof)
    v
  case ep
    of Left e  -> throwError $ show e
       Right d -> return ("date"++n, d)

--- ** bracketed dates

-- tagorbracketeddatetagsp :: Monad m => Maybe Day -> StringParser u m [Tag]
-- tagorbracketeddatetagsp mdefdate =
--   bracketeddatetagsp mdefdate <|> ((:[]) <$> tagp)

-- | Parse Ledger-style bracketed posting dates ([DATE=DATE2]), as
-- "date" and/or "date2" tags. Anything that looks like an attempt at
-- this (a square-bracketed sequence of 0123456789/-.= containing at
-- least one digit and one date separator) is also parsed, and will
-- throw an appropriate error.
--
-- The dates are parsed in full here so that errors are reported in
-- the right position. A missing year in DATE can be inferred if a
-- default date is provided. A missing year in DATE2 will be inferred
-- from DATE.
--
-- >>> rejp (bracketeddatetagsp Nothing) "[2016/1/2=3/4]"
-- Right [("date",2016-01-02),("date2",2016-03-04)]
--
-- >>> rejp (bracketeddatetagsp Nothing) "[1]"
-- Left ...not a bracketed date...
--
-- >>> rejp (bracketeddatetagsp Nothing) "[2016/1/32]"
-- Left ...line 1, column 11...bad date...
--
-- >>> rejp (bracketeddatetagsp Nothing) "[1/31]"
-- Left ...line 1, column 6...year is unknown...
--
-- >>> rejp (bracketeddatetagsp Nothing) "[0123456789/-.=/-.=]"
-- Left ...line 1, column 15...bad date, different separators...
--
bracketeddatetagsp :: Maybe Day -> ErroringJournalParser [(TagName, Day)]
bracketeddatetagsp mdefdate = do
  -- pdbg 0 "bracketeddatetagsp"
  char '['
  startpos <- getPosition
  let digits = "0123456789"
  s <- many1 (oneOf $ '=':digits++datesepchars)
  char ']'
  unless (any (`elem` s) digits && any (`elem` datesepchars) s) $
    parserFail "not a bracketed date"

  -- looks sufficiently like a bracketed date, now we
  -- re-parse as dates and throw any errors
  ctx <- getState
  ep <- parseWithCtx
    ctx{ctxYear=first3.toGregorian <$> mdefdate}
    (do
        setPosition startpos
        md1 <- optionMaybe datep
        maybe (return ()) (setYear.first3.toGregorian) md1
        md2 <- optionMaybe $ char '=' >> datep
        eof
        return (md1,md2)
    )
    s
  case ep
    of Left e          -> throwError $ show e
       Right (md1,md2) -> return $ catMaybes $
         [maybe Nothing (Just.("date",)) md1, maybe Nothing (Just.("date2",)) md2]

--- * more tests

tests_Hledger_Read_JournalReader = TestList $ concat [
    -- test_numberp
 ]

{- old hunit tests

tests_Hledger_Read_JournalReader = TestList $ concat [
    test_numberp,
    test_amountp,
    test_spaceandamountormissingp,
    test_tagcomment,
    test_inlinecomment,
    test_comments,
    test_ledgerDateSyntaxToTags,
    test_postingp,
    test_transactionp,
    [
   "modifiertransactionp" ~: do
     assertParse (parseWithCtx nullctx modifiertransactionp "= (some value expr)\n some:postings  1\n")

  ,"periodictransactionp" ~: do
     assertParse (parseWithCtx nullctx periodictransactionp "~ (some period expr)\n some:postings  1\n")

  ,"directivep" ~: do
     assertParse (parseWithCtx nullctx directivep "!include /some/file.x\n")
     assertParse (parseWithCtx nullctx directivep "account some:account\n")
     assertParse (parseWithCtx nullctx (directivep >> directivep) "!account a\nend\n")

  ,"comment" ~: do
     assertParse (parseWithCtx nullctx comment "; some comment \n")
     assertParse (parseWithCtx nullctx comment " \t; x\n")
     assertParse (parseWithCtx nullctx comment "#x")

  ,"datep" ~: do
     assertParse (parseWithCtx nullctx datep "2011/1/1")
     assertParseFailure (parseWithCtx nullctx datep "1/1")
     assertParse (parseWithCtx nullctx{ctxYear=Just 2011} datep "1/1")

  ,"datetimep" ~: do
      let p = do {t <- datetimep; eof; return t}
          bad = assertParseFailure . parseWithCtx nullctx p
          good = assertParse . parseWithCtx nullctx p
      bad "2011/1/1"
      bad "2011/1/1 24:00:00"
      bad "2011/1/1 00:60:00"
      bad "2011/1/1 00:00:60"
      good "2011/1/1 00:00"
      good "2011/1/1 23:59:59"
      good "2011/1/1 3:5:7"
      -- timezone is parsed but ignored
      let startofday = LocalTime (fromGregorian 2011 1 1) (TimeOfDay 0 0 (fromIntegral 0))
      assertParseEqual (parseWithCtx nullctx p "2011/1/1 00:00-0800") startofday
      assertParseEqual (parseWithCtx nullctx p "2011/1/1 00:00+1234") startofday

  ,"defaultyeardirectivep" ~: do
     assertParse (parseWithCtx nullctx defaultyeardirectivep "Y 2010\n")
     assertParse (parseWithCtx nullctx defaultyeardirectivep "Y 10001\n")

  ,"marketpricedirectivep" ~:
    assertParseEqual (parseWithCtx nullctx marketpricedirectivep "P 2004/05/01 XYZ $55.00\n") (MarketPrice (parsedate "2004/05/01") "XYZ" $ usd 55)

  ,"ignoredpricecommoditydirectivep" ~: do
     assertParse (parseWithCtx nullctx ignoredpricecommoditydirectivep "N $\n")

  ,"defaultcommoditydirectivep" ~: do
     assertParse (parseWithCtx nullctx defaultcommoditydirectivep "D $1,000.0\n")

  ,"commodityconversiondirectivep" ~: do
     assertParse (parseWithCtx nullctx commodityconversiondirectivep "C 1h = $50.00\n")

  ,"tagdirectivep" ~: do
     assertParse (parseWithCtx nullctx tagdirectivep "tag foo \n")

  ,"endtagdirectivep" ~: do
     assertParse (parseWithCtx nullctx endtagdirectivep "end tag \n")
     assertParse (parseWithCtx nullctx endtagdirectivep "pop \n")

  ,"accountnamep" ~: do
    assertBool "accountnamep parses a normal account name" (isRight $ parsewith accountnamep "a:b:c")
    assertBool "accountnamep rejects an empty inner component" (isLeft $ parsewith accountnamep "a::c")
    assertBool "accountnamep rejects an empty leading component" (isLeft $ parsewith accountnamep ":b:c")
    assertBool "accountnamep rejects an empty trailing component" (isLeft $ parsewith accountnamep "a:b:")

  ,"leftsymbolamountp" ~: do
    assertParseEqual (parseWithCtx nullctx leftsymbolamountp "$1")  (usd 1 `withPrecision` 0)
    assertParseEqual (parseWithCtx nullctx leftsymbolamountp "$-1") (usd (-1) `withPrecision` 0)
    assertParseEqual (parseWithCtx nullctx leftsymbolamountp "-$1") (usd (-1) `withPrecision` 0)

  ,"amount" ~: do
     let -- | compare a parse result with an expected amount, showing the debug representation for clarity
         assertAmountParse parseresult amount =
             (either (const "parse error") showAmountDebug parseresult) ~?= (showAmountDebug amount)
     assertAmountParse (parseWithCtx nullctx amountp "1 @ $2")
       (num 1 `withPrecision` 0 `at` (usd 2 `withPrecision` 0))

 ]]
-}