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simple-sql-parser/Language/SQL/SimpleSQL/Errors.hs
2024-01-09 00:07:47 +00:00

54 lines
1.6 KiB
Haskell

-- | helpers to work with parsec errors more nicely
module Language.SQL.SimpleSQL.Errors
(ParseError(..)
--,formatError
,convParseError
) where
import Text.Parsec (sourceColumn,sourceLine,sourceName,errorPos)
import qualified Text.Parsec as P (ParseError)
-- | Type to represent parse errors.
data ParseError = ParseError
{peErrorString :: String
-- ^ contains the error message
,peFilename :: FilePath
-- ^ filename location for the error
,pePosition :: (Int,Int)
-- ^ line number and column number location for the error
,peFormattedError :: String
-- ^ formatted error with the position, error
-- message and source context
} deriving (Eq,Show)
convParseError :: String -> P.ParseError -> ParseError
convParseError src e =
ParseError
{peErrorString = show e
,peFilename = sourceName p
,pePosition = (sourceLine p, sourceColumn p)
,peFormattedError = formatError src e}
where
p = errorPos e
{-
format the error more nicely: emacs format for positioning, plus
context
-}
formatError :: String -> P.ParseError -> String
formatError src e =
sourceName p ++ ":" ++ show (sourceLine p)
++ ":" ++ show (sourceColumn p) ++ ":"
++ context
++ show e
where
context =
let lns = take 1 $ drop (sourceLine p - 1) $ lines src
in case lns of
[x] -> "\n" ++ x ++ "\n"
++ replicate (sourceColumn p - 1) ' ' ++ "^\n"
_ -> ""
p = errorPos e