hledger/hledger-lib/Hledger/Utils/Parse.hs
Simon Michael 7ec25da13a web: edit/upload: normalise line endings, avoiding parse errors (#1194)
Renamed: writeValidJournal -> writeJournalTextIfValidAndChanged

Added comments clarifying line ending behaviour of:
add, import, appendToJournalFileOrStdout, readFilePortably,
writeFileWithBackupIfChanged, writeJournalTextIfValidAndChanged

Summary of current behaviour:

- hledger add and import commands will append with (at least some)
  unix line endings, possibly causing the file to have mixed line
  endings

- hledger-web edit and upload forms will write the file with
  the current system's native line endings, ie changing all
  line endings if the file previously used foreign line endings.
2020-02-24 14:04:44 -08:00

134 lines
3.8 KiB
Haskell

{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TypeFamilies #-}
module Hledger.Utils.Parse (
SimpleStringParser,
SimpleTextParser,
TextParser,
JournalParser,
ErroringJournalParser,
choice',
choiceInState,
surroundedBy,
parsewith,
parsewithString,
parseWithState,
parseWithState',
fromparse,
parseerror,
showDateParseError,
nonspace,
isNonNewlineSpace,
spacenonewline,
restofline,
eolof,
-- * re-exports
CustomErr
)
where
import Control.Monad.Except (ExceptT)
import Control.Monad.State.Strict (StateT, evalStateT)
import Data.Char
import Data.Functor.Identity (Identity(..))
import Data.List
import Data.Text (Text)
import Text.Megaparsec
import Text.Megaparsec.Char
import Text.Megaparsec.Custom
import Text.Printf
import Hledger.Data.Types
import Hledger.Utils.UTF8IOCompat (error')
-- | A parser of string to some type.
type SimpleStringParser a = Parsec CustomErr String a
-- | A parser of strict text to some type.
type SimpleTextParser = Parsec CustomErr Text -- XXX an "a" argument breaks the CsvRulesParser declaration somehow
-- | A parser of text that runs in some monad.
type TextParser m a = ParsecT CustomErr Text m a
-- | A parser of text that runs in some monad, keeping a Journal as state.
type JournalParser m a = StateT Journal (ParsecT CustomErr Text m) a
-- | A parser of text that runs in some monad, keeping a Journal as
-- state, that can throw an exception to end parsing, preventing
-- further parser backtracking.
type ErroringJournalParser m a =
StateT Journal (ParsecT CustomErr Text (ExceptT FinalParseError m)) a
-- | Backtracking choice, use this when alternatives share a prefix.
-- Consumes no input if all choices fail.
choice' :: [TextParser m a] -> TextParser m a
choice' = choice . map try
-- | Backtracking choice, use this when alternatives share a prefix.
-- Consumes no input if all choices fail.
choiceInState :: [StateT s (ParsecT CustomErr Text m) a] -> StateT s (ParsecT CustomErr Text m) a
choiceInState = choice . map try
surroundedBy :: Applicative m => m openclose -> m a -> m a
surroundedBy p = between p p
parsewith :: Parsec e Text a -> Text -> Either (ParseErrorBundle Text e) a
parsewith p = runParser p ""
parsewithString
:: Parsec e String a -> String -> Either (ParseErrorBundle String e) a
parsewithString p = runParser p ""
-- | Run a stateful parser with some initial state on a text.
-- See also: runTextParser, runJournalParser.
parseWithState
:: Monad m
=> st
-> StateT st (ParsecT CustomErr Text m) a
-> Text
-> m (Either (ParseErrorBundle Text CustomErr) a)
parseWithState ctx p s = runParserT (evalStateT p ctx) "" s
parseWithState'
:: (Stream s)
=> st
-> StateT st (ParsecT e s Identity) a
-> s
-> (Either (ParseErrorBundle s e) a)
parseWithState' ctx p s = runParser (evalStateT p ctx) "" s
fromparse
:: (Show t, Show (Token t), Show e) => Either (ParseErrorBundle t e) a -> a
fromparse = either parseerror id
parseerror :: (Show t, Show (Token t), Show e) => ParseErrorBundle t e -> a
parseerror e = error' $ showParseError e
showParseError
:: (Show t, Show (Token t), Show e)
=> ParseErrorBundle t e -> String
showParseError e = "parse error at " ++ show e
showDateParseError
:: (Show t, Show (Token t), Show e) => ParseErrorBundle t e -> String
showDateParseError e = printf "date parse error (%s)" (intercalate ", " $ tail $ lines $ show e)
nonspace :: TextParser m Char
nonspace = satisfy (not . isSpace)
isNonNewlineSpace :: Char -> Bool
isNonNewlineSpace c = c /= '\n' && isSpace c
-- XXX support \r\n ?
-- isNonNewlineSpace c = c /= '\n' && c /= '\r' && isSpace c
spacenonewline :: (Stream s, Char ~ Token s) => ParsecT CustomErr s m Char
spacenonewline = satisfy isNonNewlineSpace
restofline :: TextParser m String
restofline = anySingle `manyTill` newline
eolof :: TextParser m ()
eolof = (newline >> return ()) <|> eof