(FILECREATED "18-Dec-86 18:27:09" {QV}<NOTECARDS>1.3K>NEXT>RGPATCH007.;2
 2584   

      changes to:  (FNS NC.MakeChildLink NC.EnsureNoCycles)
		   (VARS RGPATCH007COMS)

      previous date: "18-Dec-86 18:26:12" {QV}<NOTECARDS>1.3K>NEXT>RGPATCH007.;1)


(* Copyright (c) 1986 by Xerox Corporation. All rights reserved.)

(PRETTYCOMPRINT RGPATCH007COMS)

(RPAQQ RGPATCH007COMS
 ((* * new fn for NCLINKS)
			 (FNS NC.EnsureNoCycles)
			 (P (ADDTOFILE (QUOTE NC.EnsureNoCycles)
				       (QUOTE FNS)
				       (QUOTE NCLINKS)
				       (QUOTE NC.MakeChildLink)))
			 (* * changes to NCLINKS)
			 (FNS NC.MakeChildLink)))
(* * new fn for NCLINKS)


(DEFINEQ

(NC.EnsureNoCycles

  [LAMBDA (Parent Child LinkPredicate InterestedWindow)      (* Randy.Gobbel "18-Dec-86 18:14")


          (* * Return T if no cycles via specified link predicate, else NIL.)



    (
COND

      ([for
 Link in
 (
NC.FetchToLinks
 Parent) thereis
 (
AND
 (
APPLY*
 LinkPredicate Link)
								    (
NC.SameCardP

								      Child
								      (fetch
 (Link DestinationCard)
									 of
 Link]
	(
NC.PrintMsg
 InterestedWindow NIL (
NC.RetrieveTitle
 Child)
		       " is already a child of "
		       (
NC.RetrieveTitle
 Parent)
		       (
CHARACTER
 13))
	NIL)
      ((
AND
 (
NEQ
 Parent Child)
	      (
NC.NotDaughterP
 Child Parent LinkPredicate))
	T)
      (T (
NC.PrintMsg
 InterestedWindow T (
NC.RetrieveTitle
 Child)
			" is an ancestor of "
			(
NC.RetrieveTitle
 Parent)
			(
CHARACTER
 13))
	 NIL])
)
(ADDTOFILE (QUOTE NC.EnsureNoCycles)
	   (QUOTE FNS)
	   (QUOTE NCLINKS)
	   (QUOTE NC.MakeChildLink))
(* * changes to NCLINKS)


(DEFINEQ

(NC.MakeChildLink

  [LAMBDA (Child Parent Window)                              (* Randy.Gobbel "18-Dec-86 18:26")


          (* * Tries to add Child as a child of Parent using either FiledCard or SubBox link as appropriate.

	  Won't allow if would cause a cycle. Returns new link if successful, else NIL.)




          (* * kirk 14Nov85: deleted use of PSA.Database)




          (* * rg 12/18/86: Cycle-checking code moved to NC.EnsureNoCycles)



    (DECLARE
 (
GLOBALVARS
 NC.SubBoxLinkLabel NC.FiledCardLinkLabel))
    (
AND
 (NC.EnsureNoCycles
 Parent Child (
FUNCTION
 NC.ChildLinkP)
				Window)
	   (
NC.MakeFilingLink
 Parent Child (if
 (
NC.FileBoxP
 Child T)
						 then
 NC.SubBoxLinkLabel
					       else
 NC.FiledCardLinkLabel])
)
(PUTPROPS RGPATCH007 COPYRIGHT ("Xerox Corporation" 1986))
(DECLARE: DONTCOPY
  (FILEMAP (NIL (661 1565 (NC.EnsureNoCycles 671 . 1563)) (1700 2503 (NC.MakeChildLink 1710 . 2501)))))
STOP