head2.fm.log

$ cat head2.fm

head2.IO.readline(_: Unit): IO(String)
  use line = IO.ask<String>("get_line", "")
  IO.end<String>(line)

head2: IO(Unit)
  get bind pure = IO.monad
  let io0 = pure<>(Unit.new)
  let io1 = bind<,>(io0, head2.IO.readline)
  let io2 = bind<,>(io1, IO.print)
  let io3 = bind<,>(io2, head2.IO.readline)
  bind<,>(io3, IO.print)


$ fm head2.fm
Type-checking:
head2.IO.readline: (_: Unit) -> IO(String)
head2: IO(Unit)


$ seq 3 | fmio head2
1
1
2
2
3