benchmark/tests/wc-scanStream.sml

   1 (* Written by Stephen Weeks (sweeks@sweeks.com). *)
   2
   3 structure Main =
   4    struct
   5       fun doit n =
   6          let
   7             open TextIO
   8             val f = OS.FileSys.tmpName ()
   9             val out = openOut f
  10             val _ =
  11                output (out,
  12                        String.implode
  13                        (List.tabulate (1000000, fn i =>
  14                                        if i mod 10 = 0 then #"\n" else #"a")))
  15             val _ = closeOut out
  16             fun wc f =
  17                let
  18                   val ins = openIn f
  19                in TextIO.scanStream
  20                   (fn reader => fn s =>
  21                    let
  22                       fun loop (s, ns) =
  23                          case reader s of
  24                             NONE => (closeIn ins
  25                                      ; if ns <> 100000
  26                                           then raise Fail "bug"
  27                                        else ()
  28                                      ; NONE)
  29                           | SOME (c, s') =>
  30                                loop (s', if c = #"\n" then ns + 1 else ns)
  31                    in loop (s, 0)
  32                    end)
  33                   ins
  34                end
  35             val rec loop =
  36                fn 0 => ()
  37                 | n => (wc f; loop (n - 1))
  38             val _ = loop n
  39             val _ = OS.FileSys.remove f
  40          in ()
  41          end
  42    end