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

[Hervé Pagès]

On 05/03/2017 12:04 PM, Hervé Pagès 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.
>
> 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 , Hervé Pagès <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.
>>>
>>> --
>>> Hervé Pagès
>>>
>>> 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
>>>
>>> ______________________________________________
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>>>
>>
>

-- 
Hervé Pagès

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