/
Parser.hs
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/
Parser.hs
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{- -*- mode: haskell; -*-
-}
{- PostgreSQL uses $1, $2, etc. instead of ? in query strings. So we have to
do some basic parsing on these things to fix 'em up. -}
module Database.HDBC.PostgreSQL.Parser where
import Text.ParserCombinators.Parsec
escapeseq :: GenParser Char st String
escapeseq = (try $ string "''") <|>
(try $ string "\\'")
literal :: GenParser Char st [Char]
literal = do _ <- char '\''
s <- many (escapeseq <|> (noneOf "'" >>= (\x -> return [x])))
_ <- char '\''
return $ "'" ++ (concat s) ++ "'"
qidentifier :: GenParser Char st [Char]
qidentifier = do _ <- char '"'
s <- many (noneOf "\"")
_ <- char '"'
return $ "\"" ++ s ++ "\""
comment :: GenParser Char st [Char]
comment = ccomment <|> linecomment
ccomment :: GenParser Char st [Char]
ccomment = do _ <- string "/*"
c <- manyTill ((try ccomment) <|>
(anyChar >>= (\x -> return [x])))
(try (string "*/"))
return $ "/*" ++ concat c ++ "*/"
linecomment :: GenParser Char st [Char]
linecomment = do _ <- string "--"
c <- many (noneOf "\n")
_ <- char '\n'
return $ "--" ++ c ++ "\n"
-- FIXME: handle pgsql dollar-quoted constants
qmark :: (Num st, Show st) => GenParser Char st [Char]
qmark = do _ <- char '?'
n <- getState
updateState (+1)
return $ "$" ++ show n
escapedQmark :: GenParser Char st [Char]
escapedQmark = do _ <- try (char '\\' >> char '?')
return "?"
statement :: (Num st, Show st) => GenParser Char st [Char]
statement =
do s <- many ((try escapedQmark) <|>
(try qmark) <|>
(try comment) <|>
(try literal) <|>
(try qidentifier) <|>
(anyChar >>= (\x -> return [x])))
return $ concat s
convertSQL :: String -> Either ParseError String
convertSQL input = runParser statement (1::Integer) "" input