From sokol at insa-toulouse.fr  Mon May 15 13:14:34 2017
From: sokol at insa-toulouse.fr (Serguei Sokol)
Date: Mon, 15 May 2017 13:14:34 +0200
Subject: [Rd] stopifnot() does not stop at first non-TRUE argument
In-Reply-To: <8fdb66b1-f785-ed55-6e40-a4ef8138e637@insa-toulouse.fr>
References: <64acdaeb-2857-9017-68c9-9da08e29a617@fredhutch.org>
 <E5DADF15-58C6-4F73-BC56-C6404896982F@gmail.com>
 <c2b3cb22-90bd-5372-e8b9-d1ea8b2ab828@fredhutch.org>
 <8945f7e4-99ce-53fa-46ee-cce64078a6a8@fredhutch.org>
 <22809.26921.473223.395550@stat.math.ethz.ch>
 <8fdb66b1-f785-ed55-6e40-a4ef8138e637@insa-toulouse.fr>
Message-ID: <26bd9210-e40c-0967-7abb-5f724b09c034@insa-toulouse.fr>

I see in the archives that the attachment cannot pass.
So, here is the code:
8<----
stopifnot_new <- function (...)
{
     mc <- match.call()
     n <- length(mc)-1
     if (n == 0L)
         return(invisible())
     Dparse <- function(call, cutoff = 60L) {
         ch <- deparse(call, width.cutoff = cutoff)
         if (length(ch) > 1L)
             paste(ch[1L], "....")
         else ch
     }
     head <- function(x, n = 6L) x[seq_len(if (n < 0L) max(length(x) +
         n, 0L) else min(n, length(x)))]
     abbrev <- function(ae, n = 3L) paste(c(head(ae, n), if (length(ae) >
         n) "...."), collapse = "\n  ")
     pfr <- parent.frame()
     for (i in 1L:n) {
         cl.i <- mc[[i + 1L]]
         r <- eval(cl.i, pfr)
         if (!(is.logical(r) && !anyNA(r) && all(r))) {
             msg <- if (is.call(cl.i) && identical(cl.i[[1]], quote(all.equal)) &&
                 (is.null(ni <- names(cl.i)) || length(cl.i) == 3L ||
                     length(cl.i <- cl.i[!nzchar(ni)]) == 3L))
                 sprintf(gettext("%s and %s are not equal:\n  %s"),
                     Dparse(cl.i[[2]]), Dparse(cl.i[[3]]), abbrev(r))
             else sprintf(ngettext(length(r), "%s is not TRUE", "%s are not all TRUE"),
                 Dparse(cl.i))
             stop(msg, call. = FALSE, domain = NA)
         }
     }
     invisible()
}
8<----

Best,
Serguei.

Le 15/05/2017 ? 12:48, Serguei Sokol a ?crit :
> Hello,
>
> I am a new on this list, so I introduce myself very briefly:
> my background is applied mathematics, more precisely scientific calculus
> applied for modeling metabolic systems, I am author/maintainer of
> few packages (Deriv, rmumps, arrApply).
>
> Now, on the subject of this discussion, I must say that I don't really understand
> Peter's argument:
>
>     >>> To do it differently, you would have to do something like
>     >>>
>     >>> dots <- match.call(expand.dots=FALSE)$...
>     >>>
>     >>> and then explicitly evaluate each argument in turn in the caller
>     >>> frame. This amount of nonstandard evaluation sounds like it would
>     >>> incur a performance penalty, which could be undesirable.
> The first line of the current stopifnot()
> n <- length(ll <- list(...))
> already evaluates _all_ of the arguments
> in the caller frame. So to do the same only
> on a part of them (till the first FALSE or NA occurs)
> cannot be more penalizing than the current version, right?
>
> I attach here a slightly modified version called stopifnot_new()
> which works in accordance with the man page and
> where there are only two additional calls: parent.frame() and eval().
> I don't think it can be considered as real performance penalty
> as the same or bigger amount of (implicit) evaluations was
> already done in the current version:
>
>> source("stopifnot_new.R")
>> stopifnot_new(3 == 5, as.integer(2^32), a <- 12)
> Error: 3 == 5 is not TRUE
>> a
> Error: object 'a' not found
>
> Best,
> Serguei.
>
>
> Le 15/05/2017 ? 10:39, Martin Maechler a ?crit :
>>>>>>> Herv? Pag?s <hpages at fredhutch.org>
>>>>>>>      on Wed, 3 May 2017 12:08:26 -0700 writes:
>>      > On 05/03/2017 12:04 PM, Herv? Pag?s wrote:
>>      >> Not sure why the performance penalty of nonstandard evaluation would
>>      >> be more of a concern here than for something like switch().
>>
>>      > which is actually a primitive. So it seems that there is at least
>>      > another way to go than 'dots <- match.call(expand.dots=FALSE)$...'
>>
>>      > Thanks, H.
>>
>>      >>
>>      >> If that can't/won't be fixed, what about fixing the man page so it's
>>      >> in sync with the current behavior?
>>      >>
>>      >> Thanks, H.
>>
>> Being back from vacations,...
>> I agree that something should be done here, if not to the code than at
>> least to the man page.
>>
>> For now, I'd like to look a bit longer into a possible change to the function.
>> Peter mentioned a NSE way to fix the problem and you mentioned switch().
>>
>> Originally, stopifnot() was only a few lines of code and meant to be
>> "self-explaining" by just reading its definition, and I really would like
>> to not walk too much away from that original idea.
>> How did you (Herve) think to use  switch()  here?
>>
>>
>>
>>      >> On 05/03/2017 02:26 AM, peter dalgaard wrote:
>>      >>> The first line of stopifnot is
>>      >>>
>>      >>> n <- length(ll <- list(...))
>>      >>>
>>      >>> which takes ALL arguments and forms a list of them. This implies
>>      >>> evaluation, so explains the effect that you see.
>>      >>>
>>      >>> To do it differently, you would have to do something like
>>      >>>
>>      >>> dots <- match.call(expand.dots=FALSE)$...
>>      >>>
>>      >>> and then explicitly evaluate each argument in turn in the caller
>>      >>> frame. This amount of nonstandard evaluation sounds like it would
>>      >>> incur a performance penalty, which could be undesirable.
>>      >>>
>>      >>> If you want to enforce the order of evaluation, there is always
>>      >>>
>>      >>> stopifnot(A) stopifnot(B)
>>      >>>
>>      >>> -pd
>>      >>>
>>      >>>> On 3 May 2017, at 02:50 , Herv? Pag?s <hpages at fredhutch.org>
>>      >>>> wrote:
>>      >>>>
>>      >>>> Hi,
>>      >>>>
>>      >>>> It's surprising that stopifnot() keeps evaluating its arguments
>>      >>>> after it reaches the first one that is not TRUE:
>>      >>>>
>>      >>>> > stopifnot(3 == 5, as.integer(2^32), a <- 12) Error: 3 == 5 is
>>      >>>> not TRUE In addition: Warning message: In stopifnot(3 == 5,
>>      >>>> as.integer(2^32), a <- 12) : NAs introduced by coercion to integer
>>      >>>> range > a [1] 12
>>      >>>>
>>      >>>> The details section in its man page actually suggests that it
>>      >>>> should stop at the first non-TRUE argument:
>>      >>>>
>>      >>>> ?stopifnot(A, B)? is conceptually equivalent to
>>      >>>>
>>      >>>> { if(any(is.na(A)) || !all(A)) stop(...); if(any(is.na(B)) ||
>>      >>>> !all(B)) stop(...) }
>>      >>>>
>>      >>>> Best, H.
>>      >>>>
>>      >>>> --
>>      >>>> Herv? Pag?s
>>      >>>>
>>      >>>> Program in Computational Biology Division of Public Health
>>      >>>> Sciences Fred Hutchinson Cancer Research Center 1100 Fairview
>>      >>>> Ave. N, M1-B514 P.O. Box 19024 Seattle, WA 98109-1024
>>      >>>>
>>      >>>> E-mail: hpages at fredhutch.org Phone: (206) 667-5791 Fax: (206)
>>      >>>> 667-1319
>>      >>>>
>>      >>>> ______________________________________________
>>      >>>> R-devel at r-project.org mailing list
>>      >>>> 
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Ddevel&d=DwIFaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=JwgKhKD2k-9Kedeh6pqu-A8x6UEV0INrcxcSGVGo3Tg&s=f7IKJIhpRNJMC3rZAkuI6-MTdL3GAKSV2wK0boFN5HY&e=
>>      >>>>
>>      >>>
>>      >>
>>
>>      > -- Herv? Pag?s
>>
>>      > Program in Computational Biology Division of Public Health Sciences
>>      > Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N,
>>      > M1-B514 P.O. Box 19024 Seattle, WA 98109-1024
>>
>>      > E-mail: hpages at fredhutch.org Phone: (206) 667-5791 Fax: (206)
>>      > 667-1319
>>
>>      > ______________________________________________
>>      > R-devel at r-project.org mailing list
>>      > https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>



[Rd] stopifnot() does not stop at first non-TRUE argument
Serguei Sokol