(FILECREATED " 1-Oct-78 13:02:41" <LENAT>FIX.;2 1418   

     changes to:  FIXFNS

     previous date: " 1-Oct-78 13:00:31" <LENAT>FIX.;1)


(PRETTYCOMPRINT FIXCOMS)

(RPAQQ FIXCOMS ((FNS * FIXFNS)))

(RPAQQ FIXFNS (GETFIELD))
(DEFINEQ

(GETFIELD
  [LAMBDA (FIELD SLOT UNIT)
    (CLISP: FAST)

          (* GETFIELD returns the value for a given field in a given slot in a given unit. If the operation can not be 
	  completed (eg. slot doesn't exist, or unit doesn't exist, or field is invalid, GETFIELD simply returns NIL 
	  after an appropriate error message.))


    (if (AND (EQ UNIT UA.NAME)
	     SLOT=UA.SLOTNAME)
	  or (SLOT? SLOT UNIT)
	then (if UA.SLOTREF:SLOT.ROLE MEMB '(NC S)
		 then (SLOT? SLOT UA.SLOTREF:SLOT.DATATYPE))

          (* For directly inherited and unchanged slots, reset the current unit to track back to the appropriate 
	  ancestor.)



          (* For regular slots, simply return a copy of the field.)


	     (SELECTQ FIELD
		      (VALUE UA.SLOTREF:SLOT.VALUE)
		      (ROLE UA.SLOTREF:SLOT.ROLE)
		      (DATATYPE UA.SLOTREF:SLOT.DATATYPE)
		      (DEFAULT UA.SLOTREF:SLOT.DEFAULT)
		      (CDR (FASSOC FIELD UA.SLOTREF:SLOT.FIELDS)))
      else 

          (* Distinguish between errors -
	  no UNIT or no SLOT.)


	   (if (UNIT? UNIT)
	       then (UA-ERRMSG 20 SLOT)
	     else (UA-ERRMSG 10 UNIT])
)
(DECLARE: DONTCOPY
  (FILEMAP (NIL (239 1394 (GETFIELD 251 . 1391)))))
STOP