error-of-my-while%%.lisp

CL-USER> (let ((var0 0))
	   (my-while%% (< var0 10)
	     (print var0)
	     (incf var0)))
; in: LAMBDA NIL
;     (LET ((VAR0 0))
;       (MY-WHILE%% (< VAR0 10) (PRINT VAR0) (INCF VAR0)))
; 
; caught STYLE-WARNING:
;   The variable VAR0 is defined but never used.
; 
; compilation unit finished
;   caught 1 STYLE-WARNING condition
; Evaluation aborted.
CL-USER> (let ((var1 0))
	   (my-while%% (< var1 10)
	     (print var1)
	     (incf var1)))
; in: LAMBDA NIL
;     (LET ((VAR1 0))
;       (MY-WHILE%% (< VAR1 10) (PRINT VAR1) (INCF VAR1)))
; 
; caught STYLE-WARNING:
;   The variable VAR1 is defined but never used.
; 
; compilation unit finished
;   caught 1 STYLE-WARNING condition
; Evaluation aborted.
CL-USER> 

evaluation-of-my-while.lisp

CL-USER> (let ((i 0))
	   (my-while (< i 10)
	     (print i)
	     (incf i)))

0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
9					; 返り値は9!!!
CL-USER> (let ((var0 0))
	   (my-while (< var0 10)
	     (print var0)
	     (incf var0)))

0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
9					; 多い日も安心!
CL-USER> (let ((var1 0))
	   (my-while (< var1 10)
	     (print var1)
	     (incf var1)))

0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
9					; 横モレしない!
CL-USER> 

my-while!.lisp

(defmacro! my-while! (test &body body)
  `(do ((,g!var0 nil ,@(last body))
	(,g!var1 nil ,g!var0))
       ((not ,test) ,g!var1)
     ,@(butlast body)))

my-while.lisp

(defmacro my-while (test &body body)
  ;; テンプレートの外部で var0、var1 で gensym を束縛する
  (let ((var0 (gensym)) (var1 (gensym)))
    `(do ((,var0 nil ,@(last body))
	  (,var1 nil ,var0))
	 ((not ,test) ,var1)
       ,@(butlast body))))

recursive-my-whiles.lisp

(defmacro my-while2 (test &body body)
  (let ((self (gensym)) (exp (gensym)) (acc (gensym)))
    `(labels
	 ((,self (,exp ,acc)
	    (if (not, test)
		,acc
		(,self (progn ,@body) ,exp))))
       (,self (progn ,@body) nil))))

(defmacro! my-while2! (test &body body)
  `(labels
       ((,g!self (,g!exp ,g!acc)
	  (if (not ,test)
	      ,g!acc
	      (,g!self (progn ,@body) ,g!exp))))
     (,g!self (progn ,@body) nil)))