hledger/hledger-lib/Hledger/Read/Common.hs
Simon Michael 1ec1f7c4ea more file reading cleanup, try each known format in turn
Currently this is just the journal and timelog file formats.  This is more
scalable, but when things go wrong there is no longer just a single parse
error. For now we'll just show the first error, the one from the journal
file parser.
2010-05-31 01:15:18 +00:00

73 lines
2.9 KiB
Haskell

{-|
Common utilities for hledger data readers, such as the context (state)
that is kept while parsing a journal.
-}
module Hledger.Read.Common
where
import Control.Monad.Error
import Hledger.Data.Utils
import Hledger.Data.Types (Journal)
import Hledger.Data.Journal
import System.Directory (getHomeDirectory)
import System.FilePath(takeDirectory,combine)
import System.Time (getClockTime)
import Text.ParserCombinators.Parsec
-- | A JournalUpdate is some transformation of a "Journal". It can do I/O
-- or raise an error.
type JournalUpdate = ErrorT String IO (Journal -> Journal)
-- | 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.
parseJournalWith :: (GenParser Char LedgerFileCtx JournalUpdate) -> FilePath -> String -> ErrorT String IO Journal
parseJournalWith p f s = do
tc <- liftIO getClockTime
tl <- liftIO getCurrentLocalTime
case runParser p emptyCtx f s of
Right updates -> liftM (journalFinalise tc tl f s) $ updates `ap` return nulljournal
Left err -> throwError $ show err -- XXX raises an uncaught exception if we have a parsec user error, eg from many ?
-- | Some context kept during parsing.
data LedgerFileCtx = Ctx {
ctxYear :: !(Maybe Integer) -- ^ the default year most recently specified with Y
, ctxCommod :: !(Maybe String) -- ^ I don't know
, ctxAccount :: ![String] -- ^ the current stack of parent accounts specified by !account
} deriving (Read, Show)
emptyCtx :: LedgerFileCtx
emptyCtx = Ctx { ctxYear = Nothing, ctxCommod = Nothing, ctxAccount = [] }
setYear :: Integer -> GenParser tok LedgerFileCtx ()
setYear y = updateState (\ctx -> ctx{ctxYear=Just y})
getYear :: GenParser tok LedgerFileCtx (Maybe Integer)
getYear = liftM ctxYear getState
pushParentAccount :: String -> GenParser tok LedgerFileCtx ()
pushParentAccount parent = updateState addParentAccount
where addParentAccount ctx0 = ctx0 { ctxAccount = normalize parent : ctxAccount ctx0 }
normalize = (++ ":")
popParentAccount :: GenParser tok LedgerFileCtx ()
popParentAccount = do ctx0 <- getState
case ctxAccount ctx0 of
[] -> unexpected "End of account block with no beginning"
(_:rest) -> setState $ ctx0 { ctxAccount = rest }
getParentAccount :: GenParser tok LedgerFileCtx String
getParentAccount = liftM (concat . reverse . ctxAccount) getState
expandPath :: (MonadIO m) => SourcePos -> FilePath -> m FilePath
expandPath pos fp = liftM mkRelative (expandHome fp)
where
mkRelative = combine (takeDirectory (sourceName pos))
expandHome inname | "~/" `isPrefixOf` inname = do homedir <- liftIO getHomeDirectory
return $ homedir ++ drop 1 inname
| otherwise = return inname