On Sun, Jul 24, 2011 at 09:44, Stephan Houben <steph...@planet.nl> wrote:
> Hi Rodolfo,
>
Hi Stephan,
Thanks for your considerations.
>
> I think solution 2 is generally preferred, and
> solution 1 would be considered a slight abuse of apply.
>
Why is that an abuse? Is it an abuse just in this specific case, or in
general?
I thought of (apply + a-list) as a way of expressing something like (sum
a-list), being "sum" an hypothetical function that takes a list and return
the sum of its elements.
>
> On the other hand, I find that summing comes up sufficiently
> often to deserve its own compact syntax, so I propose:
>
> ;; Solution 3
> (require (planet "mathsymbols.rkt" ("stephanh" "mathsymbols.plt" 1 0)))
>
> (Σ ([i (in-range 1 (add1 N))])
> (string-length (integer->string i)))
>
I like it. It looks neat and runs reasonably fast (and I imagine the memory
usage is on pair with the other solutions, except for #1).
I've added this to my script, now with 6 different implementations, line
after line more messy :|
(that's throw-away code anyway...)
For now it's my preferred solution considering aesthetics, semantics and
performance.
Thanks.
Rodolfo Carvalho
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