hledger/hledger-lib/Hledger/Utils/Parse.hs

168 lines
5.0 KiB
Haskell

{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TypeFamilies #-}
module Hledger.Utils.Parse (
SimpleStringParser,
SimpleTextParser,
TextParser,
-- * SourcePos
SourcePos(..),
mkPos,
unPos,
initialPos,
sourcePosPretty,
sourcePosPairPretty,
choice',
choiceInState,
surroundedBy,
parsewith,
runTextParser,
rtp,
parsewithString,
parseWithState,
parseWithState',
fromparse,
parseerror,
showDateParseError,
nonspace,
isNewline,
isNonNewlineSpace,
restofline,
eolof,
spacenonewline,
skipNonNewlineSpaces,
skipNonNewlineSpaces1,
skipNonNewlineSpaces',
-- * re-exports
HledgerParseErrors,
HledgerParseErrorData
)
where
import Control.Monad.State.Strict (StateT, evalStateT)
import Data.Char
import Data.Functor (void)
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
-- | A parser of string to some type.
type SimpleStringParser a = Parsec HledgerParseErrorData String a
-- | A parser of strict text to some type.
type SimpleTextParser = Parsec HledgerParseErrorData Text -- XXX an "a" argument breaks the CsvRulesParser declaration somehow
-- | A parser of text that runs in some monad.
type TextParser m a = ParsecT HledgerParseErrorData Text m a
-- | Render a pair of source positions in human-readable form, only displaying the range of lines.
sourcePosPairPretty :: (SourcePos, SourcePos) -> String
sourcePosPairPretty (SourcePos fp l1 _, SourcePos _ l2 c2) =
fp ++ ":" ++ show (unPos l1) ++ "-" ++ show l2'
where
l2' = if unPos c2 == 1 then unPos l2 - 1 else unPos l2 -- might be at end of file with a final new line
-- | 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 HledgerParseErrorData Text m) a] -> StateT s (ParsecT HledgerParseErrorData 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 ""
-- | Run a text parser in the identity monad. See also: parseWithState.
runTextParser, rtp
:: TextParser Identity a -> Text -> Either HledgerParseErrors a
runTextParser = parsewith
rtp = runTextParser
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 HledgerParseErrorData Text m) a
-> Text
-> m (Either HledgerParseErrors a)
parseWithState ctx p = runParserT (evalStateT p ctx) ""
parseWithState'
:: (Stream s)
=> st
-> StateT st (ParsecT e s Identity) a
-> s
-> (Either (ParseErrorBundle s e) a)
parseWithState' ctx p = runParser (evalStateT p ctx) ""
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 = errorWithoutStackTrace $ showParseError e -- PARTIAL:
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)
isNewline :: Char -> Bool
isNewline '\n' = True
isNewline _ = False
nonspace :: TextParser m Char
nonspace = satisfy (not . isSpace)
isNonNewlineSpace :: Char -> Bool
isNonNewlineSpace c = not (isNewline c) && isSpace c
spacenonewline :: (Stream s, Char ~ Token s) => ParsecT HledgerParseErrorData s m Char
spacenonewline = satisfy isNonNewlineSpace
{-# INLINABLE spacenonewline #-}
restofline :: TextParser m String
restofline = anySingle `manyTill` eolof
-- Skip many non-newline spaces.
skipNonNewlineSpaces :: (Stream s, Token s ~ Char) => ParsecT HledgerParseErrorData s m ()
skipNonNewlineSpaces = () <$ takeWhileP Nothing isNonNewlineSpace
{-# INLINABLE skipNonNewlineSpaces #-}
-- Skip many non-newline spaces, failing if there are none.
skipNonNewlineSpaces1 :: (Stream s, Token s ~ Char) => ParsecT HledgerParseErrorData s m ()
skipNonNewlineSpaces1 = () <$ takeWhile1P Nothing isNonNewlineSpace
{-# INLINABLE skipNonNewlineSpaces1 #-}
-- Skip many non-newline spaces, returning True if any have been skipped.
skipNonNewlineSpaces' :: (Stream s, Token s ~ Char) => ParsecT HledgerParseErrorData s m Bool
skipNonNewlineSpaces' = True <$ skipNonNewlineSpaces1 <|> pure False
{-# INLINABLE skipNonNewlineSpaces' #-}
eolof :: TextParser m ()
eolof = void newline <|> eof