Re: [Scheme-reports] Appeal for review help with R7RS draft 4 Denis Washington (15 Oct 2011 07:14 UTC)
Re: [Scheme-reports] Appeal for review help with R7RS draft 4 Jeronimo Pellegrini (15 Oct 2011 12:06 UTC)
Re: Appeal for review help with R7RS draft 4 Arthur A. Gleckler (16 Oct 2011 04:46 UTC)
Re: Appeal for review help with R7RS draft 4 Arthur A. Gleckler (16 Oct 2011 21:08 UTC)
Re: Appeal for review help with R7RS draft 4 Arthur A. Gleckler (17 Oct 2011 06:27 UTC)
[Scheme-reports] Legacy caar to cddddr Jussi Piitulainen (16 Oct 2011 14:45 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (17 Oct 2011 06:41 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (17 Oct 2011 23:39 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Jussi Piitulainen (20 Oct 2011 12:12 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Ray Dillinger (25 Oct 2011 00:43 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (25 Oct 2011 02:17 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (20 Oct 2011 08:21 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Ray Dillinger (20 Oct 2011 17:06 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (20 Oct 2011 17:46 UTC)
Re: Legacy caar to cddddr Arthur A. Gleckler (20 Oct 2011 17:50 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Aubrey Jaffer (20 Oct 2011 20:18 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (20 Oct 2011 22:44 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (21 Oct 2011 02:48 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Aubrey Jaffer (22 Oct 2011 00:04 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (23 Oct 2011 05:27 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (20 Oct 2011 17:52 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Grant Rettke (21 Oct 2011 02:34 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (21 Oct 2011 02:51 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (21 Oct 2011 02:56 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Grant Rettke (21 Oct 2011 20:16 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Aubrey Jaffer (22 Oct 2011 00:14 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Andre van Tonder (22 Oct 2011 14:47 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (22 Oct 2011 17:56 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Andre van Tonder (22 Oct 2011 19:15 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (22 Oct 2011 20:31 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Andre van Tonder (23 Oct 2011 08:11 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (23 Oct 2011 19:41 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Denis Washington (22 Oct 2011 19:16 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Aubrey Jaffer (24 Oct 2011 00:57 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (23 Oct 2011 05:39 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Andre van Tonder (23 Oct 2011 08:04 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Jussi Piitulainen (23 Oct 2011 11:44 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Alex Shinn (23 Oct 2011 15:16 UTC)
Re: [Scheme-reports] Legacy caar to cddddr Andre van Tonder (23 Oct 2011 16:27 UTC)
Re: [Scheme-reports] Legacy caar to cddddr John Cowan (23 Oct 2011 18:14 UTC)

Re: [Scheme-reports] Legacy caar to cddddr John Cowan 23 Oct 2011 18:12 UTC

Alex Shinn scripsit:

> > SECOND, THIRD, LIST-TAIL, etc., very much lack the elegance and
> > conciseness of the C*R notation.  For example, should the argument
> > of LIST-TAIL should be 3 or 4?
>
> So you're saying you can count the number of d's faster than you can
> read the character 3 or 4?

No, I think he is saying that he can't remember if LIST-TAIL is
zero-based or one-based.  I have no trouble remembering that it's
zero-based, just like *-REF, but to each their own brain farts.

> > Another example shows their use in small graph structures: e.g., in
> > CDADADR, the list of symbols DADAD describes a descent path in a
> > binary tree at a glance.
>
> I'm actually not concerned so much whether you call it `cadr' and
> `caddr' or `second' and `third', but this I find disturbing. `cdadadr'
> means nothing to me, and looks likely to throw inscrutable error
> messages when used incorrectly.

It means nothing to me either when applied to a list containing other
lists (and so on).  But when thinking of a structure of pairs in terms
of a binary tree, it makes complete sense: right-left-right-left-right
and there you are.  As a matter of style, then, I would use the C*R
functions when dealing with trees, but not with lists.

> This reminds me of Forth programmers insisting that they're used to
> stack operations, and it takes no effort at all to keep track of the
> stack in their head.  I believe them.

Indeed, which is why I've had no trouble implementing two Forth-like
systems but can't program in them to save my life.

--
John Cowan   cowan@ccil.org    http://ccil.org/~cowan
I am he that buries his friends alive and drowns them and draws them
alive again from the water. I came from the end of a bag, but no bag
went over me.  I am the friend of bears and the guest of eagles. I am
Ringwinner and Luckwearer; and I am Barrel-rider.  --Bilbo to Smaug

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