structure PickUnpick (*: PICKUNPICK*) = 
struct
local
    val topCount = ref 0;
in
fun pickUnpick {context, env = newenv, guid} = 
let
    val _ = topCount := !topCount + 1
    val {newenv = newenv', hash, exportLvars, hasExports} =
        PickMod.dontPickle {env = newenv, count = !topCount}
in
    {pid = (),
     pickle = (),
     exportLvars = exportLvars,
     exportPid = if hasExports then SOME hash else NONE,
     newenv = newenv'}
end (* let *)
end (* local *)
end (* struct *)