shithub: MicroHs

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Fix Show Char quotation bug.

--- a/lib/Data/Char.hs

+++ b/lib/Data/Char.hs

@@ -75,6 +75,9 @@

 isSpace :: Char -> Bool

 isSpace c = c == ' ' || c == '\t' || c == '\n'

+isAscii :: Char -> Bool

+isAscii c = c <= '\127'

+

 digitToInt :: Char -> Int

 digitToInt c | (primCharLE '0' c) && (primCharLE c '9') = ord c - ord '0'

              | (primCharLE 'a' c) && (primCharLE c 'f') = ord c - (ord 'a' - 10)

@@ -95,19 +98,23 @@

 instance Show Char where

   showsPrec _ '\'' = showString "'\\''"

-  showsPrec _ c = showChar '\'' . showString (encodeChar c) . showChar '\''

+  showsPrec _ c = showChar '\'' . showString (encodeChar c "") . showChar '\''

   showList    s = showChar '"'  . f s

     where f [] = showChar '"'

           f (c:cs) =

             if c == '"' then showString "\\\"" . f cs

-            else showString (encodeChar c) . f cs

+            else showString (encodeChar c cs) . f cs

 -- XXX should not export this

-encodeChar :: Char -> String

-encodeChar c =

+encodeChar :: Char -> String -> String

+encodeChar c rest =

   let

-    spec = [('\n', "\\n"), ('\r', "\\r"), ('\t', "\\t"), ('\b', "\\b"),

-            ('\\', "\\\\")]

-    look [] = if isPrint c then [c] else "\\" ++ show (ord c)

+    needProtect =

+      case rest of

+        [] -> False

+        c : _ -> isDigit c

+    spec = [('\a',"\\a"), ('\b', "\\b"), ('\f', "\\f"), ('\n', "\\n"),

+            ('\r', "\\r"), ('\t', "\\t"), ('\v', "\\v"), ('\\', "\\\\")]

+    look [] = if isPrint c then [c] else "\\" ++ show (ord c) ++ if needProtect then "\\&" else ""

     look ((d,s):xs) = if d == c then s else look xs

   in look spec

--- a/tests/Read.hs

+++ b/tests/Read.hs

@@ -55,4 +55,4 @@

   print (read "'\x4'" :: Char)

   print (read "\"abc\"" :: String)

   print (read "\"a\nc\"" :: String)

-  print (read "\"a\1\&c\"" :: String)

+  print (read "\"a\1\&1c\"" :: String)

-- 

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