[GHC] #11529: Show instance of Char should print literals for non-ascii printable charcters

[GHC]

#11529: Show instance of Char should print literals for non-ascii printable
charcters
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        Reporter:  nushio            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by thomie):

 You can put something like this in your `.ghci` file:
 {{{
 :seti -XScopedTypeVariables

 :{
 let myShow :: Show a => a -> String
     myShow x = go (show x) where
       go :: String -> String
       go [] = []
       go s@(x:xs) = case x of
           '\"' -> '\"' : str ++ "\"" ++ go rest
           '\'' -> '\'' : char : '\'' : go rest'
           _    -> x : go xs
         where
           (str :: String, rest):_ = reads s
           (char :: Char, rest'):_ = reads s
 :}

 :{
 let myPrint :: Show a => a -> IO ()
     myPrint = putStrLn . myShow
 :}

 :set -interactive-print=myPrint
 }}}

 Example:
 {{{
 Prelude> [(++"の父"), (++"の母")] <*> ["田中", "山田"]
 ["田中の父","山田の父","田中の母","山田の母"]
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11529#comment:4>
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