XPost: comp.lang.scheme

Barry Margolin wrote:

b) Using a nested LOOP _may_ be indicative that you didn't use LOOP >properly, as you can put almost infinite complexity into a single
LOOP.

I suppose this is possible, but I don't think it's likely. Nested loops
are extremely common whenever you're traversing multi-dimensional
structures, e.g. a 2-d array with

(loop for i upto length
do
(loop for j upto width
do
(do-something-with (aref a i j))))

or a list of lists with:

(loop for inner in outer
do
(loop for item in inner
do
(do-something-with item)))

LOOP has quite a bit of complexity, but it doesn't actually have any way to do either of these easily in a single loop (well, in the first case you
could do it with ROW-MAJOR-AREF, but that's not really a LOOP feature,
that's a special array feature).

Gauche Scheme:

(use srfi-42) ;; list-ec

(list-ec [:list i '(1 10 100)] [:list j '(7 8 9)] (* i j))

(7 8 9 70 80 90 700 800 900)

--
[T]he problem is that lispniks are as cultish as any other devout group and basically fall down frothing at the mouth if they see [heterodoxy].
--- Kenny Tilton
The good news is, it's not Lisp that sucks, but Common Lisp. --- Paul Graham

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