i got really big problem. I study at university for a second year. We 
programming at scheme, (not racket) and i have two hard quest for exams at 
scheme. My life depends on it. So i please you to help me.


 (let ((a (mcons (mcons 1 2) (mcons (mcons 3 4) '()))))
   (list (mcaar a)
(mcdar a)
(mcaadr a)
(mcdadr a))))

--> by using define-macro NOT DEFINE-SYNTAX and we HAVE TO use this 
procedure for it:
symbol?, string-upcase, symbol->string, string-length, string-ref, 
string->list, substring

I know, that were an article about this problem (i think, joah martin wrote 
that), but answers are useless for me :/ how i said, i need it in 
define-macro by using this small procedures, at school we dont know what is 
"syntax-parse" for example. 


(define test
   (lambda (collect)
     (collect 10)
     (collect 20)
     (collect 30))))

(list (test) (test) (test) (test)) ;; => (10 20 30 #<void>)

(define test2
   (lambda (collect)
     (let x ()
       (collect (random 100))
       (x))))) ..   ...this piece of code has to work also.

Quest: Implement a procedure "Make-generator" one argument, which is 
procedure one argument, which we called a generated procedure 
and evaluation will we called "collect procedure". Result of aplication is 
procedure without argument, which we called "a generator". The generator 
caused the generator to apply a procedure that once applied to a 
brightening procedure with some the argument will switch back to the place 
where it was applied generator and its result is that argument. For another 
application the generator switches the context into the generating 
procedure in the place where the pre-treatment procedure has been applied, 
etc. Once you have generate the procedure ends without applying the 
brightening procedure, the result the application of the generator is then 
an undefined value.

So please, help me, quickly ! 

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