Write a function that accepts a list and some predicates
(functions that return either true or false).
The function must subdivide the list;
the first sublist must contain the elements that satisfy
the first predicate; the second sublist must have the
elements that satisfy the second predicate; and so on.
The last sublist will contain the elements that satisfied
none of the predicates.

Gauche Scheme or Racket:

(define (predicate-collect items . preds)
(if (null? preds)
(list items)
(let-values (((yes no) (partition (car preds) items)))
(cons yes (apply predicate-collect no (cdr preds))))))

(predicate-collect
'(-5 -4 -3 -2 -1 0 1 2 3 4 5)
even?
(lambda (n) (< n 0))
(lambda (n) (> n 3)))

===>
((-4 -2 0 2 4) (-5 -3 -1) (5) (1 3))

In Forth?

On 3/11/2022, Robert L. wrote:

> the first sublist must contain the elements that satisfy
> the first predicate; the second sublist must have the
> elements that satisfy the second predicate; and so on.

Correction:

Elements that are put in a sublist are not available
for subsequent sublists.

On Friday, March 11, 2022 at 12:32:46 PM UTC+1, Robert L. wrote:
> In Forth?

Hey, our favorite incel is back! Create this one in Scheme. And do something useful with your life: https://en.wikipedia.org/wiki/Damm_algorithm

Hans Bezemer

perjantai 11. maaliskuuta 2022 klo 13.32.46 UTC+2 Robert L. kirjoitti:
> Write a function that accepts a list and some predicates
> (functions that return either true or false).
> The function must subdivide the list;
> the first sublist must contain the elements that satisfy
> the first predicate; the second sublist must have the
> elements that satisfy the second predicate; and so on.
> The last sublist will contain the elements that satisfied
> none of the predicates.
>
> Gauche Scheme or Racket:
>
> (define (predicate-collect items . preds)
> (if (null? preds)
> (list items)
> (let-values (((yes no) (partition (car preds) items)))
> (cons yes (apply predicate-collect no (cdr preds))))))
>
> (predicate-collect
> '(-5 -4 -3 -2 -1 0 1 2 3 4 5)
> even?
> (lambda (n) (< n 0))
> (lambda (n) (> n 3)))
>
> ===>
> ((-4 -2 0 2 4) (-5 -3 -1) (5) (1 3))
>
>
> In Forth?

8th:

: collect \ a a -- a
a:shift null? not if
a:new >r
_swap ( nip w:exec ) curry a:/ r@ swap a:push drop
swap ( ( w:exec nip ) curry a:/ r@ swap a:push drop ) a:each! drop
r> swap a:len if
a:push
else
drop
then
else
2drop
then ;

: app:main
[-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5]
[ ( 2 n:mod ) , ( 0 n:< ) , ( 3 n:> ) ]
collect . cr ;

On Fri, 11 Mar 2022 11:32:44 -0000 (UTC)
"Robert L." <No_spamming@noWhere_7073.org> wrote:

> Write a function that accepts a list and some predicates
[]
>
> Gauche Scheme or Racket:
>
[]
>
>
> In Forth?

Hi Gavino! Long time no see!

--
Bah, and indeed Humbug.