functor ASSOCLIST( type Item eqtype Key ):DictSig =
struct
    type Item = Item
    and  Key  = Key
    exception Lookup
    datatype Dict = D of (Key * Item) list
        val empty = D []
        
        fun lookup (D((k,e)::t)) key = if(k = key)then e
                                        else lookup (D t) key
          | lookup _ _ = raise Lookup

        fun rem _ [] = []
          | rem key ((entry as (k,_))::t) = if(k = key) then t
                                       else entry :: rem key t

        fun enter ((k,e), D entries) = D((k, e) :: rem k entries)

        fun remove (key, D entries) = D(rem key entries)

        fun alist (D l) = l
end;