-- u2b: utf8 string to byte string
-- b2u: the reverse

split x y  = MPS.split (x.u2b) (y.u2b) .map b2u
gsub x y z = MPS.gsub (x.u2b) (y.u2b) (z.u2b) .b2u
match x y  = MPS.match (x.u2b) (y.u2b)

read_file  = readFile
write_file = writeFile
ls x       = MPS.ls (x.u2b) ^ map b2u
mkdir_p    = u2b >>> createDirectoryIfMissing True

file_exist = u2b >>> doesFileExist
dir_exist  = u2b >>> doesDirectoryExist