Exclude PCRE metacharacters in Haskell
1 answer
I am not aware of such a function in any of the PCRE libraries, but depending on what you are trying to accomplish, you can use the PCRE Declaration:
{-# LANGUAGE OverloadedStrings #-}
import qualified Data.ByteString.Char8 as B
import Text.Regex.PCRE
quotePCRE bs = B.concat [ "\\Q" , bs , "\\E" ]
-- Of course, this won't work if the
-- string to be quoted contains `\E` ,
-- but that would be much eaiser to fix
-- than writing a function taking into
-- account all the necessary escaping.
literal = "^[$100]$"
quoted = quotePCRE literal
main :: IO ()
main = do B.putStr "literal: " >> B.putStrLn literal
-- literal: ^[$100]$
B.putStr "quoted: " >> B.putStrLn quoted
-- quoted: \Q^[$100]$\E
putStrLn "literal =~ literal :: Bool"
print ( literal =~ literal :: Bool )
-- literal =~ literal :: Bool
-- False
putStrLn "literal =~ quoted :: Bool"
print ( literal =~ quoted :: Bool )
-- literal =~ quoted :: Bool
-- True
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