utf 8 - Read file with UTF-8 in Haskell as IO String -

i have following code works fine unless file has utf-8 characteres :

module main import ref main =     text <- getline     theinput <- readfile text     writefile ("a"++text) (unlist . proc . lines $ theinput) 

with utf-8 characteres this: hgetcontents: invalid argument (invalid byte sequence)

since file i'm working has utf-8 characters, handle exception in order reuse functions imported ref if possible.

is there way read utf-8 file io string can reuse ref's functions?. modifications should make code?. in advance.

i attach functions declarations ref module:

unlist :: [string] -> string proc :: [string] -> [string] 

from prelude:

lines :: string -> [string] 

this can done ghc's basic (but extended standard) system.io module, although you'll have use more functions:

module main  import ref import system.io  main =     text <- getline     inputhandle <- openfile text readmode      hsetencoding inputhandle utf8     theinput <- hgetcontents inputhandle     outputhandle <- openfile ("a"++text) writemode     hsetencoding outputhandle utf8     hputstr outputhandle (unlist . proc . lines $ theinput)     hclose outputhandle -- guess 1 optional in case.