signature SET =
  sig
    type set
    type element
    
    val empty : set
    val add : set * element -> set
    val delete : set * element -> set
    val is_member : set * element -> bool
    val union : set * set -> set
    val intersection : set * set -> set
    (* etc. etc. *)

    val fold : ('a * element -> 'a) -> 'a * set -> 'a
  end;


signature SERVER =
  sig
    type connection
    type server_address

    val open_connection : server_address -> connection
    val close_connection : connection -> unit
  end;

signature DEFECT_TRACKER =
  sig
    include SERVER

    type issue
    type fix
    type filespec
    type marker
    type changelist
    type field
    type value
    
    structure IssueSet : SET
    sharing type IssueSet.element = issue
   
    structure ValueSet : SET
    sharing type ValueSet.element = value
    
    val changed_issues : connection -> issueSet.set * marker
    val mark_changed_issues_done : connection * marker -> connection
    
    val issue_human_name : connection * issue -> string	(* "ENH00034" / "job000034" *)

    val issue_to_id : connection * issue -> string	(* "33" / "job000034" *)
    val id_to_issue : connection * string -> issue
    
    val issue_field : connection * issue * field -> value
    val set_issue_field : connection * issue * field * value -> issue * connection
    val commit_issue : connection * issue -> connection
    
  end;

signature PERFORCE =
  sig
    include DEFECT_TRACKER
  end;

signature TEAMTRACK =
  sig
    include DEFECT_TRACKER
  end;

functor TeamTrack (
  structure TeamShareAPI : TEAMSHAREAPI
) : TEAMTRACK =
  struct
    type connection = TeamShareAPI.server
    type server_address = string * string * string * int  (* user, password, hostname, port *)

    fun open_connection (user, password, hostname, port) =
      TeamShareAPI.connect (user, password, hostname ^ ":" ^ int_to_string(port))

    fun close_connection ...
    
    val cases_table = TeamShareAPI.table("CASES")
    
    fun changed_issues connection =
      TeamShareAPI.query (connection, cases_table, "TS_P4DTI_RID = 
     
  end;


signature FIELD_MAPPING =