Show instance for non-ascii characters prints their character codes. This is sad for Haskell users that speaks language other than English.
'A' 'A' 'Ä' '\196' '漢' '\28450' print $ [(++"'s dad"), (++"'s mom")] <*> ["Simon", "John"] ["Simon's dad","John's dad","Simon's mom","John's mom"] print $ [(++"の父"), (++"の母")] <*> ["田中", "山田"] ["\30000\20013\12398\29238","\23665\30000\12398\29238","\30000\20013\12398\27597","\23665\30000\12398\27597"]
The function that needs improvement is showLitChar in GHC.Show, which currently prints any character larger than ASCII code 127 by its character code: http://haddock.stackage.org/lts-5.1/base-4.8.2.0/src/GHC-Show.html showLitChar :: Char -> ShowS showLitChar c s | c > '\DEL' = showChar '\\' (protectEsc isDec (shows (ord c)) s) On the other hand, there is GHC.Unicode.isPrint, the predicate for printable Unicode characters, that is calling on a foreign function u_iswprint for the knowledge. https://hackage.haskell.org/package/base-4.8.2.0/docs/src/GHC.Unicode.html#i... I think one of the solution is to import and call u_iswprint from GHC.Show, too, but I don't know it's against any design choices. Yesterday, I had a chance to teach Haskell (in Japanese,) and I had to use English in some of the most exciting examples, like the Applicative List example above. I would heartedly like to see GHC improve in these directions, so that we can make more happy learning materials on Haskell. Let me ask your opinions on what is the best way to do this (or is better not to do this), before I submit something to GHC Trac. Best, -------------------------------- -- Takayuki MURANUSHI -- RIKEN Advanced Institute for Computational Science -- http://nushio3.github.io/ -- http://www.geocities.jp/takascience/ --------------------------------