Links.Def

(*
https://web.archive.org/web/20041226015509/http://www.oberon.ethz.ch:80/ethoberon/defs/Links.Def.html
*)
DEFINITION Links; (* portable *)

(*The Links module manage a set of named references to objects for the gadgets.
*)
 IMPORT
  Files, Objects;

 TYPE
  Link = POINTER TO LinkDesc;
  LinkDesc = RECORD
   next: Link;
   name: ARRAY 32 OF CHAR;
   obj: Objects.Object
  END;

(* Store links to a file. Only (ref, lib) references to links are written. *)
 PROCEDURE StoreLinks (VAR R: Files.Rider; lib: Objects.Library; list: Link);

(* Load links from a file. *)
 PROCEDURE LoadLinks (VAR R: Files.Rider; lib: Objects.Library; VAR list: Link);

(* Copy links.  Both shallow and deep copies are supported. *)
 PROCEDURE CopyLinks (VAR M: Objects.CopyMsg; in: Link; VAR out: Link);

(* Bind all linked objects. *)
 PROCEDURE BindLinks (list: Link; VAR M: Objects.BindMsg);

(* Insert a link in a list. An existing link with the same name is discarded.
*)
 PROCEDURE InsertLink (VAR list: Link; name: ARRAY OF CHAR; val: Link);

(* Link Locate. *)
 PROCEDURE FindLink (name: ARRAY OF CHAR; list: Link): Link;

(* Delete a link. *)
 PROCEDURE DeleteLink (VAR list: Link; name: ARRAY OF CHAR);

(* Default handling of setting, retrieving and enumerating a list of links.
Parameter list might be modified
during a set operation. *)
 PROCEDURE HandleLinkMsg (VAR list: Link; VAR M: Objects.LinkMsg);

(* Forward a message to all linked objects in the list. USE WITH CARE, MESSAGE
CYCLES! *)
 PROCEDURE Broadcast (list: Link; VAR M: Objects.ObjMsg);

(* Get the named link of obj. *)
 PROCEDURE GetLink (obj: Objects.Object; name: ARRAY OF CHAR; VAR ob1: Objects.Object);

(* Set the named link of obj. *)
 PROCEDURE SetLink (obj: Objects.Object; name: ARRAY OF CHAR; ob1: Objects.Object);

END Links.

(* Remarks:

1. The links of gadgets (both Gadgets.Object and Gadgets.Frame) are managed
by module Gadgets. Module Gadgets use the utility procedures defined in module
Links.

*)