mlyacc/examples/fol/interface.sml

   1 (* Externally visible aspects of the lexer and parser *)
   2
   3 signature INTERFACE =
   4 sig
   5
   6 type pos
   7 val line : pos ref
   8 val init_line : unit -> unit
   9 val next_line : unit -> unit
  10 val error : string * pos * pos -> unit
  11
  12 type arg
  13 val nothing : arg
  14
  15 end  (* signature INTERFACE *)
  16
  17 functor Interface () : INTERFACE =
  18 struct
  19
  20 type pos = int
  21 val line = ref 0
  22 fun init_line () = (line := 1)
  23 fun next_line () = (line := !line + 1)
  24 fun error (errmsg,line:pos,_) =
  25   TextIO.output(TextIO.stdOut,"Line " ^ (Int.toString line) ^ ": " ^ errmsg ^ "\n")
  26
  27 type arg = unit
  28
  29 val nothing = ()
  30
  31 end  (* functor INTERFACE *)