On Wed, Feb 12, 2025 at 08:14:04AM +0100, Alexander Burger wrote:
> If a problem is a linear operation, like traversing a list, a loop is
> more natural for me. For traversing a tree, recursion is better of
> course.
Hmm, it seems that I begin to detect some advantages in tco/tc :)
For example, in pil64 I had a function calculating the digits of pi ad
infinitum:
# Print next digit of PI
(de piDigit ()
(job '((Q . 1) (R . 0) (S . 1) (K . 1) (N . 3) (L . 3))
(while (>= (- (+ R (* 4 Q)) S) (* N S))
(mapc set '(Q R S K N L)
(list
(* Q K)
(* L (+ R (* 2 Q)))
(* S L)
(inc K)
(/ (+ (* Q (+ 2 (* 7 K))) (* R L)) (* S L))
(+ 2 L) ) ) )
(setq
Q (* 10 Q)
R (* 10 (- R (* N S))) )
(swap 'N M) ) )
# Print all digits of PI
(prin (piDigit) ".")
(loop
(prin (piDigit))
(flush) )
We see, it has a 'while' loop using 'set' and 'list' to get an atomic
assignment of the six variables.
Now, here tco/tc come in handy, as it *is* a loop with atomic
assignment! :)
# Print next digit of PI
(de piDigit ()
(job '((Q . 1) (R . 0) (S . 1) (K . 1) (N . 3) (L . 3))
(tco (Q R S K N L)
(if (>= (- (+ R (* 4 Q)) S) (* N S))
(tc
(* Q K)
(* L (+ R (* 2 Q)))
(* S L)
(inc K)
(/ (+ (* Q (+ 2 (* 7 K))) (* R L)) (* S L))
(+ 2 L) )
(setq
Q (* 10 Q)
R (* 10 (- R (* N S))) )
(swap 'N M) ) ) ) )
# Print all digits of PI
(prin (piDigit) ".")
(loop
(prin (piDigit))
(flush) )
Looks more clean!
3.14159265358979323846264338327950288419716939937510582097494459230781640...
☺/ A!ex
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