Where are usages like "== 2L" documented?

-----Original Message-----
From: Gabor Grothendieck [mailto:ggrothendieck at gmail.com]
Sent: Monday, November 16, 2009 4:52 PM
To: Duncan Murdoch
Cc: Steven McKinney; R Help
Subject: Re: [R] Where are usages like "== 2L" documented?

On Mon, Nov 16, 2009 at 7:25 PM, Duncan Murdoch <murdoch at stats.uwo.ca>
wrote:

On 16/11/2009 6:47 PM, Steven McKinney wrote:

?NumericConstants

will bring up a help page that mentions
"All other numeric constants start with a digit or period and are

either a

decimal or hexadecimal constant optionally followed by L."

and

"An numeric constant immediately followed by L is regarded as an

integer

number when possible (and with a warning if it contains a "."). "

The word "integer" in the above sentence of the NumericConstants help
page is hyperlinked to the integer() function page.  There is then no
example or discussion of L there.

but I haven't found discussion of it anywhere else in the help

pages.

Others may know what other help pages discuss this.

I'm surprised that the help page invoked from
?integer
does not discuss this. ?Anyone know why not?

This is part of the syntax of the language. ?It has nothing to do

with the

integer() function, which is what ?integer is asking about.

It might be useful to have a SeeAlso to NumericConstants on that help
page for those who looked up ?integer thinking it might be about
integer constants.

Yes, additional discussion of "L" would be very valuable.  I've had
several people ask me about usages, as this original poster did.
I think that increased use of L has outpaced updating of help entries.
Given that L is appearing in more places, I'd like to request additional
discussion of it and examples using it in help pages.

class(1L)

[1] "integer"

storage.mode(1L)

[1] "integer"

Since "integer" is the term often associated with this language construct,
that seems a natural place to say something about it, and direct users
to other appropriate help pages.

The help page for storage.mode() shows an example with "1i" in it,
could "1L" please also be added?  ("1.0" or "1." would also be useful.)

cex3 <- c("NULL","1","1:1","1i","list(1)","data.frame(x=1)",
  "pairlist(pi)", "c", "lm", "formals(lm)[[1]]",  "formals(lm)[[2]]",
  "y~x","expression((1))[[1]]", "(y~x)[[1]]",
  "expression(x <- pi)[[1]][[1]]")


The "L" language construct is often used in length checks such as
in the sample() function " if (length(x) == 1L ..."

The length() function help page discusses
" The default method currently returns an integer of length 1."
again with the "integer" hyperlinked to the integer() help page.
Since length() therefore can only assess integer lengths
from 0 to about 2^31 - 1 it would be helpful to discuss this
integer "L" construct and the range of values that can be expressed
with mode "integer" more fully somewhere in one of these help topics.

sample

function (x, size, replace = FALSE, prob = NULL) 
{
    if (length(x) == 1L && is.numeric(x) && x >= 1) {
        if (missing(size)) 
            size <- x
        .Internal(sample(x, size, replace, prob))
    }
    else {
        if (missing(size)) 
            size <- length(x)
        x[.Internal(sample(length(x), size, replace, prob))]
    }
}
<environment: namespace:base>


Best
Steve McKinney