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|
{-# LANGUAGE NoImplicitPrelude #-}
{- |
Module : Text.Pandoc.CSV
Copyright : Copyright (C) 2017–2019 John MacFarlane <jgm@berkeley.edu>
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Simple CSV parser.
-}
module Text.Pandoc.CSV (
CSVOptions(..),
defaultCSVOptions,
parseCSV,
ParseError
) where
import Prelude
import Control.Monad (void)
import Data.Text (Text)
import qualified Data.Text as T
import Text.Parsec
import Text.Parsec.Text (Parser)
data CSVOptions = CSVOptions{
csvDelim :: Char
, csvQuote :: Char
, csvKeepSpace :: Bool -- treat whitespace following delim as significant
, csvEscape :: Maybe Char -- default is to double up quote
} deriving (Read, Show)
defaultCSVOptions :: CSVOptions
defaultCSVOptions = CSVOptions{
csvDelim = ','
, csvQuote = '"'
, csvKeepSpace = False
, csvEscape = Nothing }
parseCSV :: CSVOptions -> Text -> Either ParseError [[Text]]
parseCSV opts t = parse (pCSV opts) "csv" t
pCSV :: CSVOptions -> Parser [[Text]]
pCSV opts =
(pCSVRow opts `sepEndBy` endline) <* (spaces *> eof)
pCSVRow :: CSVOptions -> Parser [Text]
pCSVRow opts = notFollowedBy blank >> pCSVCell opts `sepBy` pCSVDelim opts
blank :: Parser ()
blank = try $ spaces >> (() <$ endline <|> eof)
pCSVCell :: CSVOptions -> Parser Text
pCSVCell opts = pCSVQuotedCell opts <|> pCSVUnquotedCell opts
pCSVQuotedCell :: CSVOptions -> Parser Text
pCSVQuotedCell opts = do
char (csvQuote opts)
res <- many (satisfy (\c -> c /= csvQuote opts &&
Just c /= csvEscape opts) <|> escaped opts)
char (csvQuote opts)
return $ T.pack res
escaped :: CSVOptions -> Parser Char
escaped opts =
case csvEscape opts of
Nothing -> try $ char (csvQuote opts) >> char (csvQuote opts)
Just c -> try $ char c >> noneOf "\r\n"
pCSVUnquotedCell :: CSVOptions -> Parser Text
pCSVUnquotedCell opts = T.pack <$>
many (satisfy (\c -> c /= csvDelim opts && c /= '\r' && c /= '\n'
&& c /= csvQuote opts))
pCSVDelim :: CSVOptions -> Parser ()
pCSVDelim opts = do
char (csvDelim opts)
if csvKeepSpace opts
then return ()
else skipMany (oneOf " \t")
endline :: Parser ()
endline = do
optional (void $ char '\r')
void $ char '\n'
|
