I'm learning scheme (using guile) and I found the need to create an initial alist, with some keys and empty lists as their values. I was wondering what's the best practice when doing something like this. My goal is to keep this alist around so I can later add items to the lists. This is what I have now:
(define buckets
`((hourly . ())
(daily . ())
(monthly . ())
(yearly . ())))
However, this does not work when trying to assoc-set!, to append items to the list. This, however, works:
(define buckets
(acons 'hourly '()
(acons 'daily '()
(acons 'monthly '()
(acons 'yearly '() '())))))
Clearly not the best looking piece of code. Is there a more idiomatic way of building such an alist? Maybe I'm doing this completely wrong. The end goal is to have these buckets that I can refer to later in different parts of code by their key.
Thanks!
scheme@(guile-user)> (acons 'hourly '()
(acons 'daily '()
(acons 'monthly '()
(acons 'yearly '() '()))))
$2 = ((hourly) (daily) (monthly) (yearly))
is the same as
scheme@(guile-user)> '((hourly) (daily) (monthly) (yearly))
$3 = ((hourly) (daily) (monthly) (yearly))
scheme@(guile-user)> (equal? $2 $3)
$4 = #t
EDIT assoc-set! doesn't work in this case because these lists are not mutable. One way to achieve a mutable list while still shortening the way to define it is to use this expression instead:
(map list '(hourly daily montly yearly))