]> Git — Sourcephile - comptalang.git/blob - lib/Hcompta/Format/Ledger/Read.hs
Modification : filtre dès la lecture pour moins de consommation mémoire.
[comptalang.git] / lib / Hcompta / Format / Ledger / Read.hs
1 {-# LANGUAGE DeriveDataTypeable #-}
2 {-# LANGUAGE FlexibleContexts #-}
3 {-# LANGUAGE NamedFieldPuns #-}
4 {-# LANGUAGE OverloadedStrings #-}
5 {-# LANGUAGE ScopedTypeVariables #-}
6 {-# LANGUAGE TupleSections #-}
7 {-# LANGUAGE TypeFamilies #-}
8 module Hcompta.Format.Ledger.Read where
9
10 -- import Control.Applicative ((<$>), (<*>), (<*))
11 import qualified Control.Exception as Exception
12 import Control.Arrow ((***))
13 import Control.Monad (guard, join, liftM)
14 import Control.Monad.IO.Class (liftIO)
15 import Control.Monad.Trans.Except (ExceptT(..), throwE)
16 import Control.Monad.Trans.Class (lift)
17 import qualified Data.Char
18 import qualified Data.Either
19 import qualified Data.List
20 import Data.List.NonEmpty (NonEmpty(..))
21 import qualified Data.Map.Strict as Data.Map
22 import Data.Maybe (fromMaybe)
23 import Data.String (fromString)
24 import qualified Data.Time.Calendar as Time
25 import qualified Data.Time.Clock as Time
26 import qualified Data.Time.LocalTime as Time
27 import Data.Typeable ()
28 import qualified Text.Parsec as R hiding
29 ( char
30 , anyChar
31 , crlf
32 , newline
33 , noneOf
34 , oneOf
35 , satisfy
36 , space
37 , spaces
38 , string
39 )
40 import Text.Parsec (Stream, ParsecT, (<|>), (<?>))
41 import qualified Text.Parsec.Pos as R
42 import qualified Data.Text.IO as Text.IO (readFile)
43 import qualified Data.Text as Text
44 import qualified System.FilePath.Posix as Path
45
46 import qualified Hcompta.Balance as Balance
47 import qualified Hcompta.Account as Account
48 import Hcompta.Account (Account)
49 import qualified Hcompta.Amount as Amount
50 import qualified Hcompta.Amount.Style as Style
51 import qualified Hcompta.Amount.Read as Amount.Read
52 import qualified Hcompta.Amount.Unit as Unit
53 import qualified Hcompta.Date as Date
54 import Hcompta.Date (Date)
55 import qualified Hcompta.Date.Read as Date.Read
56 import qualified Hcompta.Format.Ledger as Ledger
57 import Hcompta.Format.Ledger
58 ( Comment
59 , Journal(..)
60 , Posting(..), Posting_Type(..)
61 , Tag, Tag_Name, Tag_Value, Tag_by_Name
62 , Transaction(..)
63 )
64 import Hcompta.Lib.Consable (Consable(..))
65 import qualified Hcompta.Lib.Regex as Regex
66 import Hcompta.Lib.Regex (Regex)
67 import qualified Hcompta.Lib.Parsec as R
68 import qualified Hcompta.Lib.Path as Path
69
70 data Context ts t
71 = Context
72 { context_account_prefix :: !(Maybe Account)
73 , context_aliases_exact :: !(Data.Map.Map Account Account)
74 , context_aliases_joker :: ![(Account.Joker, Account)]
75 , context_aliases_regex :: ![(Regex, Account)]
76 , context_date :: !Date
77 , context_unit_and_style :: !(Maybe (Amount.Unit, Amount.Style))
78 , context_journal :: !(Journal ts t)
79 , context_year :: !Date.Year
80 } deriving (Show)
81
82 context :: Consable ts t => Journal ts t -> Context ts t
83 context context_journal =
84 Context
85 { context_account_prefix = Nothing
86 , context_aliases_exact = Data.Map.empty
87 , context_aliases_joker = []
88 , context_aliases_regex = []
89 , context_date = Date.nil
90 , context_unit_and_style = Nothing
91 , context_journal
92 , context_year = Date.year Date.nil
93 }
94
95 data Error
96 = Error_date Date.Read.Error
97 | Error_transaction_not_equilibrated Transaction [Balance.Unit_Sum (Balance.Posting_Amount Ledger.Posting)]
98 | Error_virtual_transaction_not_equilibrated Transaction [Balance.Unit_Sum (Balance.Posting_Amount Ledger.Posting)]
99 | Error_reading_file FilePath Exception.IOException
100 | Error_including_file FilePath [R.Error Error]
101 deriving (Show)
102
103 -- * Read 'Account'
104
105 account_name_sep :: Char
106 account_name_sep = ':'
107
108 -- | Read an 'Account'.
109 account :: Stream s m Char => ParsecT s u m Account
110 account = do
111 R.notFollowedBy $ R.space_horizontal
112 Account.from_List <$> do
113 R.many1_separated account_name $ R.char account_name_sep
114
115 -- | Read an Account.'Account.Name'.
116 account_name :: Stream s m Char => ParsecT s u m Account.Name
117 account_name = do
118 fromString <$> do
119 R.many1 $ R.try account_name_char
120 where
121 account_name_char :: Stream s m Char => ParsecT s u m Char
122 account_name_char = do
123 c <- R.anyChar
124 case c of
125 _ | c == comment_begin -> R.parserZero
126 _ | c == account_name_sep -> R.parserZero
127 _ | R.is_space_horizontal c -> do
128 _ <- R.notFollowedBy $ R.space_horizontal
129 return c <* (R.lookAhead $ R.try $
130 ( R.try (R.char account_name_sep)
131 <|> account_name_char
132 ))
133 _ | not (Data.Char.isSpace c) -> return c
134 _ -> R.parserZero
135
136 -- | Read an Account.'Account.Joker_Name'.
137 account_joker_name :: Stream s m Char => ParsecT s u m Account.Joker_Name
138 account_joker_name = do
139 n <- R.option Nothing $ (Just <$> account_name)
140 case n of
141 Nothing -> R.char account_name_sep >> (return $ Account.Joker_Any)
142 Just n' -> return $ Account.Joker_Name n'
143
144 -- | Read an Account.'Account.Joker'.
145 account_joker :: Stream s m Char => ParsecT s u m Account.Joker
146 account_joker = do
147 R.notFollowedBy $ R.space_horizontal
148 R.many1_separated account_joker_name $ R.char account_name_sep
149
150 -- | Read a 'Regex'.
151 account_regex :: Stream s m Char => ParsecT s u m Regex
152 account_regex = do
153 re <- R.many1 $ R.satisfy (not . R.is_space_horizontal)
154 Regex.of_StringM re
155
156 -- | Read an Account.'Account.Filter'.
157 account_pattern :: Stream s m Char => ParsecT s u m Account.Pattern
158 account_pattern = do
159 R.choice_try
160 [ Account.Pattern_Exact <$> (R.char '=' >> account)
161 , Account.Pattern_Joker <$> (R.char '*' >> account_joker)
162 , Account.Pattern_Regex <$> (R.option '~' (R.char '~') >> account_regex)
163 ]
164
165 -- * Directives
166
167 directive_alias :: (Consable ts t, Stream s m Char) => ParsecT s (Context ts t) m ()
168 directive_alias = do
169 _ <- R.string "alias"
170 R.skipMany1 $ R.space_horizontal
171 pattern <- account_pattern
172 R.skipMany $ R.space_horizontal
173 _ <- R.char '='
174 R.skipMany $ R.space_horizontal
175 repl <- account
176 R.skipMany $ R.space_horizontal
177 case pattern of
178 Account.Pattern_Exact acct -> R.modifyState $ \ctx -> ctx{context_aliases_exact=
179 Data.Map.insert acct repl $ context_aliases_exact ctx}
180 Account.Pattern_Joker jokr -> R.modifyState $ \ctx -> ctx{context_aliases_joker=
181 (jokr, repl):context_aliases_joker ctx}
182 Account.Pattern_Regex regx -> R.modifyState $ \ctx -> ctx{context_aliases_regex=
183 (regx, repl):context_aliases_regex ctx}
184 return ()
185
186 -- * Read 'Comment'
187
188 comment_begin :: Char
189 comment_begin = ';'
190
191 comment :: Stream s m Char => ParsecT s u m Comment
192 comment = (do
193 _ <- R.char comment_begin
194 fromString <$> do
195 R.manyTill R.anyChar (R.lookAhead R.new_line <|> R.eof)
196 ) <?> "comment"
197
198 comments :: Stream s m Char => ParsecT s u m [Comment]
199 comments = (do
200 R.try $ do
201 _ <- R.spaces
202 R.many1_separated comment (R.new_line >> R.skipMany R.space_horizontal)
203 <|> return []
204 ) <?> "comments"
205
206 -- * Read 'Tag'
207
208 tag_value_sep :: Char
209 tag_value_sep = ':'
210
211 tag_sep :: Char
212 tag_sep = ','
213
214 -- | Read a 'Tag'.
215 tag :: Stream s m Char => ParsecT s u m Tag
216 tag = (do
217 n <- tag_name
218 _ <- R.char tag_value_sep
219 v <- tag_value
220 return (n, v)
221 ) <?> "tag"
222
223 tag_name :: Stream s m Char => ParsecT s u m Tag_Name
224 tag_name = do
225 fromString <$> do
226 R.many1 $ R.satisfy (\c -> c /= tag_value_sep && not (Data.Char.isSpace c))
227
228 tag_value :: Stream s m Char => ParsecT s u m Tag_Value
229 tag_value = do
230 fromString <$> do
231 R.manyTill R.anyChar $ do
232 R.lookAhead $ do
233 R.try (R.char tag_sep >> R.many R.space_horizontal >> tag_name >> R.char tag_value_sep >> return ())
234 <|> R.try R.new_line
235 <|> R.eof
236
237 tags :: Stream s m Char => ParsecT s u m Tag_by_Name
238 tags = do
239 Ledger.tag_by_Name <$> do
240 R.many_separated tag $ do
241 _ <- R.char tag_sep
242 R.skipMany $ R.space_horizontal
243 return ()
244
245 not_tag :: Stream s m Char => ParsecT s u m ()
246 not_tag = do
247 R.skipMany $ R.try $ do
248 R.skipMany $ R.satisfy
249 (\c -> c /= tag_value_sep
250 && not (Data.Char.isSpace c))
251 R.space_horizontal
252
253 -- * Read 'Posting'
254
255 posting
256 :: (Consable ts t, Stream s (R.Error_State Error m) Char, Monad m)
257 => ParsecT s (Context ts t) (R.Error_State Error m) (Posting, Posting_Type)
258 posting = (do
259 ctx <- R.getState
260 sourcepos <- R.getPosition
261 R.skipMany1 $ R.space_horizontal
262 status_ <- status
263 R.skipMany $ R.space_horizontal
264 acct <- account
265 let (type_, account_) = posting_type acct
266 amounts_ <-
267 R.choice_try
268 [ do
269 _ <- R.count 2 R.space_horizontal
270 R.skipMany $ R.space_horizontal
271 maybe id (\(u, s) ->
272 if u == Unit.nil then id
273 else
274 Data.Map.adjust (\a ->
275 a{ Amount.style = s{Style.precision = Style.precision $ Amount.style a}
276 , Amount.unit = u })
277 Unit.nil)
278 (context_unit_and_style ctx) .
279 Amount.from_List <$> do
280 R.many_separated Amount.Read.amount $ do
281 R.skipMany $ R.space_horizontal
282 _ <- R.char amount_sep
283 R.skipMany $ R.space_horizontal
284 return ()
285 , return Data.Map.empty
286 ] <?> "amounts"
287 R.skipMany $ R.space_horizontal
288 -- TODO: balance assertion
289 -- TODO: conversion
290 comments_ <- comments
291 let tags_ = tags_of_comments comments_
292 dates_ <-
293 case Data.Map.lookup "date" tags_ of
294 Nothing -> return []
295 Just dates -> do
296 let date2s = Data.Map.lookup "date2" tags_ -- NOTE: support hledger's date2
297 do
298 (flip mapM) (dates ++ fromMaybe [] date2s) $ \s ->
299 R.runParserT_with_Error_fail "tag date" id
300 (Date.Read.date Error_date (Just $ context_year ctx) <* R.eof) ()
301 (Text.unpack s) s
302 >>= \dates_ -> case (dates, date2s) of -- NOTE: put hledger's date2 at least in second position
303 ([], Just (_:_)) ->
304 return $ context_date ctx:dates_
305 _ -> return $ dates_
306 return (Posting
307 { posting_account=account_
308 , posting_amounts=amounts_
309 , posting_comments=comments_
310 , posting_dates=dates_
311 , posting_sourcepos=sourcepos
312 , posting_status=status_
313 , posting_tags=tags_
314 }, type_)
315 ) <?> "posting"
316
317 amount_sep :: Char
318 amount_sep = '+'
319
320 tags_of_comments :: [Comment] -> Tag_by_Name
321 tags_of_comments =
322 Data.Map.unionsWith (++)
323 . Data.List.map
324 ( Data.Either.either (const Data.Map.empty) id
325 . R.runParser (not_tag >> tags <* R.eof) () "" )
326
327 status :: Stream s m Char => ParsecT s u m Ledger.Status
328 status = (do
329 ( R.try $ do
330 R.skipMany $ R.space_horizontal
331 _ <- (R.char '*' <|> R.char '!')
332 return True )
333 <|> return False
334 ) <?> "status"
335
336 -- | Return the 'Posting_Type' and stripped 'Account' of the given 'Account'.
337 posting_type :: Account -> (Posting_Type, Account)
338 posting_type acct =
339 fromMaybe (Posting_Type_Regular, acct) $ do
340 case acct of
341 name:|[] ->
342 case Text.stripPrefix virtual_begin name of
343 Just name' -> do
344 name'' <-
345 Text.stripSuffix virtual_end name'
346 >>= return . Text.strip
347 guard $ not $ Text.null name''
348 Just (Posting_Type_Virtual, name'':|[])
349 Nothing -> do
350 name' <-
351 Text.stripPrefix virtual_balanced_begin name
352 >>= Text.stripSuffix virtual_balanced_end
353 >>= return . Text.strip
354 guard $ not $ Text.null name'
355 Just (Posting_Type_Virtual_Balanced, name':|[])
356 first_name:|acct' -> do
357 let rev_acct' = Data.List.reverse acct'
358 let last_name = Data.List.head rev_acct'
359 case Text.stripPrefix virtual_begin first_name
360 >>= return . Text.stripStart of
361 Just first_name' -> do
362 last_name' <-
363 Text.stripSuffix virtual_end last_name
364 >>= return . Text.stripEnd
365 guard $ not $ Text.null first_name'
366 guard $ not $ Text.null last_name'
367 Just $
368 ( Posting_Type_Virtual
369 , first_name':|
370 Data.List.reverse (last_name':Data.List.tail rev_acct')
371 )
372 Nothing -> do
373 first_name' <-
374 Text.stripPrefix virtual_balanced_begin first_name
375 >>= return . Text.stripStart
376 last_name' <-
377 Text.stripSuffix virtual_balanced_end last_name
378 >>= return . Text.stripEnd
379 guard $ not $ Text.null first_name'
380 guard $ not $ Text.null last_name'
381 Just $
382 ( Posting_Type_Virtual_Balanced
383 , first_name':|
384 Data.List.reverse (last_name':Data.List.tail rev_acct')
385 )
386 where
387 virtual_begin = Text.singleton posting_type_virtual_begin
388 virtual_end = Text.singleton posting_type_virtual_end
389 virtual_balanced_begin = Text.singleton posting_type_virtual_balanced_begin
390 virtual_balanced_end = Text.singleton posting_type_virtual_balanced_end
391
392 posting_type_virtual_begin :: Char
393 posting_type_virtual_begin = '('
394 posting_type_virtual_balanced_begin :: Char
395 posting_type_virtual_balanced_begin = '['
396 posting_type_virtual_end :: Char
397 posting_type_virtual_end = ')'
398 posting_type_virtual_balanced_end :: Char
399 posting_type_virtual_balanced_end = ']'
400
401 -- * Read 'Transaction'
402
403 transaction
404 :: (Consable ts t, Stream s (R.Error_State Error m) Char, Monad m)
405 => ParsecT s (Context ts t) (R.Error_State Error m) Transaction
406 transaction = (do
407 ctx <- R.getState
408 transaction_sourcepos <- R.getPosition
409 transaction_comments_before <-
410 comments
411 >>= \x -> case x of
412 [] -> return []
413 _ -> return x <* R.new_line
414 date_ <- Date.Read.date Error_date (Just $ context_year ctx)
415 dates_ <-
416 R.option [] $ R.try $ do
417 R.skipMany $ R.space_horizontal
418 _ <- R.char date_sep
419 R.skipMany $ R.space_horizontal
420 R.many_separated
421 (Date.Read.date Error_date (Just $ context_year ctx)) $
422 R.try $ do
423 R.many $ R.space_horizontal
424 >> R.char date_sep
425 >> (R.many $ R.space_horizontal)
426 let transaction_dates = (date_, dates_)
427 R.skipMany $ R.space_horizontal
428 transaction_status <- status
429 transaction_code <- R.option "" $ R.try code
430 R.skipMany $ R.space_horizontal
431 transaction_description <- description
432 R.skipMany $ R.space_horizontal
433 transaction_comments_after <- comments
434 let transaction_tags =
435 Data.Map.unionWith (++)
436 (tags_of_comments transaction_comments_before)
437 (tags_of_comments transaction_comments_after)
438 R.new_line
439 (postings_unchecked, postings_not_regular) <-
440 ((Ledger.posting_by_Account . Data.List.map fst) *** id) .
441 Data.List.partition ((Posting_Type_Regular ==) . snd) <$>
442 R.many1_separated posting R.new_line
443 let (transaction_virtual_postings, balanced_virtual_postings_unchecked) =
444 join (***) (Ledger.posting_by_Account . Data.List.map fst) $
445 Data.List.partition ((Posting_Type_Virtual ==) . snd)
446 postings_not_regular
447 let tr_unchecked =
448 Transaction
449 { transaction_code
450 , transaction_comments_before
451 , transaction_comments_after
452 , transaction_dates
453 , transaction_description
454 , transaction_postings=postings_unchecked
455 , transaction_virtual_postings
456 , transaction_balanced_virtual_postings=balanced_virtual_postings_unchecked
457 , transaction_sourcepos
458 , transaction_status
459 , transaction_tags
460 }
461 transaction_postings <-
462 case Balance.infer_equilibrium postings_unchecked of
463 (_, Left ko) -> R.fail_with "transaction infer_equilibrium"
464 (Error_transaction_not_equilibrated tr_unchecked ko)
465 (_bal, Right ok) -> return ok
466 transaction_balanced_virtual_postings <-
467 case Balance.infer_equilibrium balanced_virtual_postings_unchecked of
468 (_, Left ko) -> R.fail_with "transaction infer_equilibrium"
469 (Error_virtual_transaction_not_equilibrated tr_unchecked ko)
470 (_bal, Right ok) -> return ok
471 return $
472 tr_unchecked
473 { transaction_postings
474 , transaction_balanced_virtual_postings
475 }
476 ) <?> "transaction"
477
478 date_sep :: Char
479 date_sep = '='
480
481 code :: (Consable ts t, Stream s m Char) => ParsecT s (Context ts t) m Ledger.Code
482 code = (do
483 fromString <$> do
484 R.skipMany $ R.space_horizontal
485 R.between (R.char '(') (R.char ')') $
486 R.many $ R.satisfy (\c -> c /= ')' && not (R.is_space_horizontal c))
487 ) <?> "code"
488
489 description :: Stream s m Char => ParsecT s u m Ledger.Description
490 description = (do
491 fromString <$> do
492 R.many $ R.try description_char
493 ) <?> "description"
494 where
495 description_char :: Stream s m Char => ParsecT s u m Char
496 description_char = do
497 c <- R.anyChar
498 case c of
499 _ | c == comment_begin -> R.parserZero
500 _ | R.is_space_horizontal c -> return c <* (R.lookAhead $ R.try $ description_char)
501 _ | not (Data.Char.isSpace c) -> return c
502 _ -> R.parserZero
503
504 -- * Read directives
505
506 default_year :: (Consable ts t, Stream s m Char) => ParsecT s (Context ts t) m ()
507 default_year = (do
508 year <- R.integer_of_digits 10 <$> R.many1 R.digit
509 R.skipMany R.space_horizontal >> R.new_line
510 context_ <- R.getState
511 R.setState context_{context_year=year}
512 ) <?> "default year"
513
514 default_unit_and_style :: (Consable ts t, Stream s m Char) => ParsecT s (Context ts t) m ()
515 default_unit_and_style = (do
516 amount_ <- Amount.Read.amount
517 R.skipMany R.space_horizontal >> R.new_line
518 context_ <- R.getState
519 R.setState context_{context_unit_and_style =
520 Just $
521 ( Amount.unit amount_
522 , Amount.style amount_ )}
523 ) <?> "default unit and style"
524
525 include ::
526 ( Consable ts Transaction
527 , Show (ts Transaction)
528 , Stream s (R.Error_State Error IO) Char
529 )
530 => ParsecT s (Context ts Transaction) (R.Error_State Error IO) ()
531 include = (do
532 sourcepos <- R.getPosition
533 filename <- R.manyTill R.anyChar (R.lookAhead R.new_line <|> R.eof)
534 context_ <- R.getState
535 let journal_ = context_journal context_
536 let cwd = Path.takeDirectory (R.sourceName sourcepos)
537 file_path <- liftIO $ Path.abs cwd filename
538 content <- do
539 join $ liftIO $ Exception.catch
540 (liftM return $ readFile file_path)
541 (return . R.fail_with "include reading" . Error_reading_file file_path)
542 (journal_included, context_included) <- do
543 liftIO $
544 R.runParserT_with_Error (R.and_state $ journal_rec file_path)
545 context_{context_journal = Ledger.journal}
546 file_path content
547 >>= \x -> case x of
548 Right ok -> return ok
549 Left ko -> R.fail_with "include parsing" (Error_including_file file_path ko)
550 R.setState $
551 context_included{context_journal=
552 journal_{journal_includes=
553 journal_included{journal_file=file_path}
554 : journal_includes journal_}}
555 ) <?> "include"
556
557 -- * Read 'Journal'
558
559 journal ::
560 ( Consable ts Transaction
561 , Show (ts Transaction)
562 , Stream s (R.Error_State Error IO) Char
563 )
564 => FilePath
565 -> ParsecT s (Context ts Transaction) (R.Error_State Error IO) (Journal ts Transaction)
566 journal file_ = (do
567 currentLocalTime <- liftIO $
568 Time.utcToLocalTime
569 <$> Time.getCurrentTimeZone
570 <*> Time.getCurrentTime
571 let (currentLocalYear, _, _) = Time.toGregorian $ Time.localDay currentLocalTime
572 context_ <- R.getState
573 R.setState $ context_{context_year=currentLocalYear}
574 journal_rec file_
575 ) <?> "journal"
576
577 journal_rec ::
578 ( Consable ts Transaction
579 , Show (ts Transaction)
580 , Stream s (R.Error_State Error IO) Char
581 )
582 => FilePath
583 -> ParsecT s (Context ts Transaction) (R.Error_State Error IO) (Journal ts Transaction)
584 journal_rec file_ = do
585 last_read_time <- lift $ liftIO Time.getCurrentTime
586 R.skipMany $ do
587 R.choice_try
588 [ R.skipMany1 R.space
589 , (do (R.choice_try
590 [ R.string "Y" >> return default_year
591 , R.string "D" >> return default_unit_and_style
592 , R.string "!include" >> return include
593 ] <?> "directive")
594 >>= \r -> R.skipMany1 R.space_horizontal >> r)
595 , ((do
596 t <- transaction
597 context_' <- R.getState
598 let j = context_journal context_'
599 R.setState $ context_'{context_journal=
600 j{journal_transactions=mcons t $ journal_transactions j}}
601 R.new_line <|> R.eof))
602 , R.try (comment >> return ())
603 ]
604 R.eof
605 journal_ <- context_journal <$> R.getState
606 return $
607 journal_
608 { journal_file = file_
609 , journal_last_read_time = last_read_time
610 , journal_includes = reverse $ journal_includes journal_
611 }
612
613 -- ** Read 'Journal' from a file
614
615 file
616 ::
617 ( Consable ts Transaction
618 , Show (ts Transaction)
619 )
620 => Context ts Transaction
621 -> FilePath
622 -> ExceptT [R.Error Error] IO (Journal ts Transaction)
623 file ctx path = do
624 ExceptT $
625 Exception.catch
626 (liftM Right $ Text.IO.readFile path) $
627 \ko -> return $ Left $
628 [ R.Error_Custom (R.initialPos path) $ Error_reading_file path ko ]
629 >>= liftIO . R.runParserT_with_Error (journal path) ctx path
630 >>= \x -> case x of
631 Left ko -> throwE $ ko
632 Right ok -> ExceptT $ return $ Right ok