[Rd] Re: [R] Is k equivalent to k:k ?

Richard A. O'Keefe ok at cs.otago.ac.nz
Sun Dec 12 22:56:48 CET 2004

I asked:

> In this discussion of seq(), can anyone explain to
> me _why_ seq(to=n) and seq(length=3) have different
> types?  

Martin Maechler <maechler at stat.math.ethz.ch> replied:
	well, the explantion isn't hard:  look at  seq.default  :-)
That's the "efficient cause", I was after the "final cause".
That is, I wasn't asking "what is it about the system which MAKES this
happen" but "why does anyone WANT this to happen"?

	now if that really makes your *life* simpler, what does that
	tell us about your life  ;-) :-)
It tells you I am revising someone else's e-book about S to describe R.
The cleaner R is, the easier that part of my life gets.

	 In the future, we really might want to have a new type,
	 some "long integer" or "index" which would be used both in R
	 and C's R-API for indexing into large objects where 32-bit
	 integers overflow.

It would be useful needed now for large file support and for Java interfacing.

	 I assume, we will keep the    R "integer" == C "int" == 32-bit int
	 forever, but need something with more bits rather sooner than later.
	 But in any, case by then, some things might have to change in
	 R (and C's R-API) storage type of indexing.
seq: from, to, by, length[.out], along[.with]

	I'm about to fix this (documentation, not code).
Please don't.  There's a lot of text out there: tutorials, textbooks,
S on-inline documentation, &c which states over and over again that
the arguments are 'along' and 'with'.  Change the documentation, and 
people will start writing length.out, and will that port to S-Plus?
(Serious question:  I don't know.)

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