--
--
-- IO
--
--

--
-- IO
--
def print {a} (x: a) : IO () :=
  do write x
     write "\n"
     flush ()

def printToPort {a, b} (port: a) (x: b) : IO () :=
  do writeToPort port x
     writeToPort port "\n"

def display {a} (x: a) : IO () :=
  do write x
     flush ()

def displayToPort {a, b} (port: a) (x: b) : IO () := do writeToPort port x

def eachLine (proc: String -> IO ()) : IO () :=
  do let eof := isEof ()
     if eof
       then return ()
       else do let line := readLine ()
               proc line
               eachLine proc

def eachLineFromPort {a} (port: a) (proc: String -> IO ()) : IO () :=
  do let eof := isEofPort port
     if eof
       then return ()
       else do let line := readLineFromPort port
               proc line
               eachLineFromPort port proc

def eachFile (files: [String]) (proc: String -> IO ()) : IO () :=
  match files as list string with
    | [] -> return ()
    | $file :: $rest ->
      do let port := openInputFile file
         () <- eachLineFromPort port proc
         () <- closeInputPort port
         eachFile rest proc

--
-- Collection
--
def each {a} (proc: a -> IO ()) (xs: [a]) : IO () :=
  match xs as list something with
    | [] -> do return ()
    | $x :: $rs ->
      do proc x
         each proc rs

--
-- Debug
--
def debug expr :=
  io $ do print (show expr)
          return expr

def debug2 msg expr :=
  io $ do display msg
          print (show expr)
          return expr