;; Function To Be Tested: UNDO  (Programmer's Assistant Command)
;;
;; Source: Xerox Common Lisp Implementation Notes (Lyric Beta Release)
;;		 Section 20.2 (The Evaluator), Page 27
;; Section: The Evaluator
;; Page: 28
;;
;; Created By:   John Park
;;
;; Creation Date: Feb 24, 1987
;;
;; Last Update:   
;;
;; Filed As:      {ERIS}<lispcore>test>exec>undo.u
;;
;;
;; Syntax:        UNDO  &rest EVENT-SPEC
;;
;; Function Description: Undo the side effects of the specified event.  The UNDO
;; command is implemented by "watching" the evaluation of forms and requiring
;; undoable operations in that evaluation to save enough information on the history
;; list to reverse their side effects.  The Exec simply executes operations, and 
;; any undoable changes that occur are automatically saved on the history list by
;; the responsible functions.  The UNDO command works on itself the same way:
;; it recovers the saved information and performs the corresponding inverses.
;; thus, UNDO is effective on itself, so that the user can UNDO an UNDO, and UNDO
;; that, etc.
;; 
;; Argument(s):  EVENT-SPEC
;;			  
;; Returns:     See function description
;;
;; Constraints/Limitations: Due to the nature of Programmer's Assistant commands,
;; testing them will not be totally automatic.  Comments are incorporated within 
;; each command file, which will be run by using the function bksysbuf.  
;; Each test setup is titled "COMMAND-TEST-SETUP", which executes the command 
;; string. The do-test form within the command file will return T or "test 
;; failed" This test file requires TEDIT package.  
;;
;;
;; Messages will be printed before each command in the command files is executed
;; for user monitoring.   Test result is logged on 
;; {eris}<lispcore>test>exec>test.report. 

(DO-TEST "UNDO-TEST-SETUP"
	(PROGN 
		(SETQ MESS1 "Now do-test will determine if correct results have been produced when UNDOs were entered...")
		(SETQ TEST-RESULT "{ERIS}<LISPCORE>TEST>EXEC>TEST.REPORT")
		(DEFUN R-FORMAT (STATUS)
				(FORMAT *OUTPUT* "~2%COMMAND: UNDO~%STATUS:  ~A  DATE:  ~A  TESTER:  ~A~%" STATUS (IL:DATE) IL:USERNAME))

(SETQ UNDO-COMMAND-STRING 
"; Unbound all undo variables
(MAPCAR #'MAKUNBOUND '(UNDO-VAR UNDO-VAR-1 UNDO-VAR-2))
(SETQ UNDO-VAR 'YES)
(SETQ UNDO-VAR-1 'YES-NO)
; this undoes undo-var
UNDO -2
(IF (NOT (BOUNDP 'UNDO-VAR)) (SETQ UNDO-VAR 'UNBOUND) (SETQ UNDO-VAR 'BOUND))
(SETQ UNDO-VAR-2 'YES-NO)
(SETQ UNDO-VAR-2 'NO)
; This undoes the last event and undo-var-2 is still bound
UNDO
(IF (EQ UNDO-VAR-2 'YES-NO) (SETQ UNDO-VAR-2F 'STILL-BOUND) (SETQ UNDO-VAR-2F 'GONE))
; this will restore the value of undo-var-2 to its first value
UNDO UNDO
(IF (EQ UNDO-VAR-2 'NO) (SETQ UNDO-VAR-2R 'RESTORED) (SETQ UNDO-VAR-2R 'SAME))
(FORMAT NIL MESS1)
(DO-TEST 'UNDO-TEST-RESULT
   	(PROG2 (SETQ *OUTPUT* (OPEN TEST-RESULT :DIRECTION :OUTPUT
		 		:IF-EXISTS  :APPEND))
            (IF (AND (EQ UNDO-VAR 'UNBOUND)
				(EQ UNDO-VAR-2F 'STILL-BOUND)
				(EQ UNDO-VAR-2R 'RESTORED))
				(PROGN (R-FORMAT 'SUCCESS) T)
				(PROGN (R-FORMAT 'FAIL) NIL))
             (CLOSE *OUTPUT*)
	)
)
")
		(IL:BKSYSBUF UNDO-COMMAND-STRING)
	)
)

STOP