Kon Lovett wrote:
(define (fib)
(let loop ((a 1) (b 1))
(set! fib (lambda () (loop b (+ a b))))
a))
;; maybe non-portable outside of current chicken semantics?
Except for the caveat about some compilers, no. However the above
doesn't "make" a generator, in the sense that it can be reused. To
restart the sequence 'fib' must be rebound. Certainly not
"disgusting", just of limited use.
I've used the idiom for more complex generators with multiple yield
points but it quickly becomes tangled. I don't like the programming
style that too many generators afford, so I don't do this so much. I
usually use generator for generating ids where
http://okmij.org/ftp/Scheme/monad-in-Scheme.html would use either a
global variable or a state monad.
Sunnan
_______________________________________________
Chicken-users mailing list
Chicken-users@nongnu.org
http://lists.nongnu.org/mailman/listinfo/chicken-users
