Let Arc die? What makes you think the number of posters here in any way reflects the chances of Arc "living" or "dying", whatever that means? People need to chill out and give things some ... time.
I know, I know, I just asked this question b/c I saw someone else's post about dotted pair containing lists (old timers would say "s-expressions") not working properly in some cases in arc, and I having noodled around implementing lisp in ruby recently, and having stubbed my toe on implementing cons after having chosen arrays as the underlying implementation of lists, I thought I'd throw this out there and see what people had to say.
Neh, what I meant was, you can have a thing that quacks like a list and never see the need for a dotted pair.
That can be hidden below the abstraction. See, case in point, lists/arrays in Ruby, which are more or less lists without the car and cdr part. Although, you do get a 'nil' if you access beyond the end of the array. ;-)
Ruby lists can quack? Bah, let me know when they can mate, that's when you know you have the same species: ie, can two Ruby more-or-less lists have shared structure, formed say by ruby-consing a different element onto the same list?
And ducks can nest. How about Ruby lists? I have always thought the language should have been called Trep, for Tree Processing language. Can I build a Ruby tree and then quickly flatten by juggling some Ruby ducktails?
As for "That can be hidden below the abstraction", OK, now you have a duck: moving smoothly on the surface and paddling like crazy beneath.
The whole comparison just seems (sorry on more levels than one) daffy.
Indeed, you are correct. Ruby[1] doesn't have "native" lists, it has native arrays. Observe:
irb(main):001:0> [].class
=> Array
There is no Ruby cons, nor Ruby car, nor Ruby cdr. There is y.unshift x or [x] + y for cons (though these cannot constructed "dotted Arrays"), arr[0] or arr.first for car, and arr[1..-1] for cdr, but they denote no structure-sharing. However, flattening would merely be arr.flatten—of course it doesn't work by cdr-juggling, but that's because there are no cdrs.
I'm not really sure what the grandparent post means: "lists without the car and cdr part"? That sounds to me like a very good definition of an... array![2]
Also, that set of duck puns/references was fantastic. Well done.
[1]: Which is a very nice language.
[2]: Well, without the O(1) access time, but I digress.
I can take no credit -- they just popped out of my keyboard. There must be some poorly understood connection between algorithms, data structures, and waterfowl.
Actually, they (the infamous "they") did a study, and apparently, ducks are the funniest animal. Take that with as large a grain of salt as you think is appropriate :)
I see that; it just seems like they don't have a huge amount of practical utility. I mean, they're nice to have, but when I was programming in CL, one rarely if ever saw them in production code.
But I think you're right -- they have that "feeling the bits between your toes" character.
They're not necessary in order to have a list abstraction, but they are the minimal thing you could build lists out of.
The whole point of the axiomatic approach is that you don't program in the axioms themselves. But you still do want to have the things you do program in built out of the smallest set of axioms.
My experience (with emacs, and emacs-lisp, anyway) is that the docstrings are incredibly valuable to me, and that the culture of emacs hackers leads the doc strings to be maintained pretty well.
However, I've never seen anyone use the docstrings in any of the common lisp programming jobs I've held. Which is why I invoke the "culture of emacs hackers" above.
