Apologies - more chat than programming, but: fwiw, for part 1, I just
defined simple
one-liner functions "forward" etc which worked ok. For part 2, they
needed redefining, and,
yes, I used direct defs; nothing as sophisticated as fold!
I've done days 1-17, mostly straightforward, some very fiddly.
But I'm stuck at 18, which is v complicated in its explanation. I
started with boxes in J,
but found navigation hard - I haven't used nested structures much in J -
so resorted to
working on the untranslated rows, using ;: to separate the symbols &
numbers, but
couldn't get all the examples to reproduce the stated results! So
I've wasted yet more time
learning - or relearning - how to deal with nested arrays in Dyalog APL
and remembering how
to use John Scholes' dfns. Managed to "reduce" the "addition" of the
first pair of snailnumbers,
but reducing the "addition" of the third line defeats me. I suppose I'm
sometimes inserting
some result at the wrong depth.
I've spent so much time on that that I'll probably give up the rest!
Cheers,
Mike
On 22/12/2021 14:59, Raul Miller wrote:
(responding to
http://jsoftware.com/pipermail/programming/2021-December/059436.html#)
I am not sure that I thought this example out well enough for it to be
good on an examples page.
For instance, after thinking about it for just a few minutes, I realized that
b2fold=: 0 0 0&(}.F..{{
'dH0 dA0 N'=. x
'A H D'=. y
dA=: N*dA0
dH=: N*dH0
dD=: A*dH
y+dA,dH,dD
}})
b2=: {{*/b2fold y}}
would have been clearer.
(Originally I was using ]F.. and commenting that I needed to drop the
first item of the result. But isn't it clearer to include that drop
mechanism with the fold implementation?)
But (and this is worse): this particular example lacks utility, which
means that it's not going to be very interesting for anyone.
Other opportunities will arise, though. And I think that your concept
of linked example pages is a good one and worth following up on.
Thanks,
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