R devel - May 2017 - stopifnot() does not stop at first non-TRUE argument

switch(i, ...)
extracts 'i'-th argument in '...'. It is like
eval(as.name(paste0("..", i))) .

Just mentioning other things:
- For 'n',
n <- nargs()
can be used.
- sys.call() can be used in place of match.call() .
---------------------------
>>>>> peter dalgaard <pdalgd at gmail.com>
>>>>>     on Mon, 15 May 2017 16:28:42 +0200 writes:
    > I think Herv?'s idea was just that if switch can evaluate arguments
selectively, so can stopifnot(). But switch() is .Primitive, so does it from C.

if he just meant that, then "yes, of course" (but not so interesting).

    > I think it is almost a no-brainer to implement a sequential stopifnot
if dropping to C code is allowed. In R it gets trickier, but how about this:

Something like this, yes, that's close to what Serguei Sokol had proposed
(and of course I *do*  want to keep the current sophistication
 of stopifnot(), so this is really too simple)

    > Stopifnot <- function(...)
    > {
    > n <- length(match.call()) - 1
    > for (i in 1:n)
    > {
    > nm <- as.name(paste0("..",i))
    > if (!eval(nm)) stop("not all true")
    > }
    > }
    > Stopifnot(2+2==4)
    > Stopifnot(2+2==5, print("Hey!!!") == "Hey!!!")
    > Stopifnot(2+2==4, print("Hey!!!") == "Hey!!!")
    > Stopifnot(T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,F,T)


    >> On 15 May 2017, at 15:37 , Martin Maechler <maechler at
stat.math.ethz.ch> wrote:
    >> 
    >> I'm still curious about Herv?'s idea on using  switch() 
for the
    >> issue.

    > -- 
    > Peter Dalgaard, Professor,
    > Center for Statistics, Copenhagen Business School
    > Solbjerg Plads 3, 2000 Frederiksberg, Denmark
    > Phone: (+45)38153501
    > Office: A 4.23
    > Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com

> On 16 May 2017, at 18:37 , Suharto Anggono Suharto Anggono via R-devel
<r-devel at r-project.org> wrote:
> 
> switch(i, ...)
> extracts 'i'-th argument in '...'. It is like
> eval(as.name(paste0("..", i))) .
Hey, that's pretty neat! 

-pd
> 
> Just mentioning other things:
> - For 'n',
> n <- nargs()
> can be used.
> - sys.call() can be used in place of match.call() .
> ---------------------------
>>>>>> peter dalgaard <pdalgd at gmail.com>
>>>>>>    on Mon, 15 May 2017 16:28:42 +0200 writes:
> 
>> I think Herv?'s idea was just that if switch can evaluate arguments
selectively, so can stopifnot(). But switch() is .Primitive, so does it from C.
> 
> if he just meant that, then "yes, of course" (but not so
interesting).
> 
>> I think it is almost a no-brainer to implement a sequential stopifnot
if dropping to C code is allowed. In R it gets trickier, but how about this:
> 
> Something like this, yes, that's close to what Serguei Sokol had
proposed
> (and of course I *do*  want to keep the current sophistication
> of stopifnot(), so this is really too simple)
> 
>> Stopifnot <- function(...)
>> {
>> n <- length(match.call()) - 1
>> for (i in 1:n)
>> {
>> nm <- as.name(paste0("..",i))
>> if (!eval(nm)) stop("not all true")
>> }
>> }
>> Stopifnot(2+2==4)
>> Stopifnot(2+2==5, print("Hey!!!") == "Hey!!!")
>> Stopifnot(2+2==4, print("Hey!!!") == "Hey!!!")
>> Stopifnot(T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,F,T)
> 
> 
>>> On 15 May 2017, at 15:37 , Martin Maechler <maechler at
stat.math.ethz.ch> wrote:
>>> 
>>> I'm still curious about Herv?'s idea on using  switch() 
for the
>>> issue.
> 
>> -- 
>> Peter Dalgaard, Professor,
>> Center for Statistics, Copenhagen Business School
>> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
>> Phone: (+45)38153501
>> Office: A 4.23
>> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
> 
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com

On 05/16/2017 09:59 AM, peter dalgaard wrote:
>
>> On 16 May 2017, at 18:37 , Suharto Anggono Suharto Anggono via R-devel
<r-devel at r-project.org> wrote:
>>
>> switch(i, ...)
>> extracts 'i'-th argument in '...'. It is like
>> eval(as.name(paste0("..", i))) .
>
> Hey, that's pretty neat!
Indeed! Seems like this topic is even more connected to switch()
than I anticipated...

H.
>
> -pd
>
>>
>> Just mentioning other things:
>> - For 'n',
>> n <- nargs()
>> can be used.
>> - sys.call() can be used in place of match.call() .
>> ---------------------------
>>>>>>> peter dalgaard <pdalgd at gmail.com>
>>>>>>>    on Mon, 15 May 2017 16:28:42 +0200 writes:
>>
>>> I think Herv?'s idea was just that if switch can evaluate
arguments selectively, so can stopifnot(). But switch() is .Primitive, so does
it from C.
>>
>> if he just meant that, then "yes, of course" (but not so
interesting).
>>
>>> I think it is almost a no-brainer to implement a sequential
stopifnot if dropping to C code is allowed. In R it gets trickier, but how about
this:
>>
>> Something like this, yes, that's close to what Serguei Sokol had
proposed
>> (and of course I *do*  want to keep the current sophistication
>> of stopifnot(), so this is really too simple)
>>
>>> Stopifnot <- function(...)
>>> {
>>> n <- length(match.call()) - 1
>>> for (i in 1:n)
>>> {
>>> nm <- as.name(paste0("..",i))
>>> if (!eval(nm)) stop("not all true")
>>> }
>>> }
>>> Stopifnot(2+2==4)
>>> Stopifnot(2+2==5, print("Hey!!!") == "Hey!!!")
>>> Stopifnot(2+2==4, print("Hey!!!") == "Hey!!!")
>>> Stopifnot(T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,F,T)
>>
>>
>>>> On 15 May 2017, at 15:37 , Martin Maechler <maechler at
stat.math.ethz.ch> wrote:
>>>>
>>>> I'm still curious about Herv?'s idea on using  switch()
for the
>>>> issue.
>>
>>> --
>>> Peter Dalgaard, Professor,
>>> Center for Statistics, Copenhagen Business School
>>> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
>>> Phone: (+45)38153501
>>> Office: A 4.23
>>> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
>>
>> ______________________________________________
>> 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=DwIGaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=mLJLORFCunDiCafHllurGVVVHiMf85ExkM7B5DngfIk&s=helOsmplADBmY6Ct7r30onNuD8a6GKz6yuSgjPxljeU&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

>>>>> Suharto Anggono Suharto Anggono via R-devel <r-devel at
r-project.org>
>>>>>     on Tue, 16 May 2017 16:37:45 +0000 writes:
    > switch(i, ...)
    > extracts 'i'-th argument in '...'. It is like
    > eval(as.name(paste0("..", i))) .

Yes, that's neat.

It is only almost the same:  in the case of illegal 'i'
the switch() version returns
    invisible(NULL)

whereas the version we'd want should signal an error, typically
the same error message as

  > t2 <- function(...) ..2
  > t2(1)
  Error in t2(1) (from #1) : the ... list does not contain 2 elements
  > 


    > Just mentioning other things:
    > - For 'n',
    > n <- nargs()
    > can be used.

I know .. [in this case, where '...' is the only formal argument of the
function]

    > - sys.call() can be used in place of match.call() .

Hmm... in many cases, yes.... notably, as we do *not* want the
argument names here, I think you are right.


    > ---------------------------
>>>>> peter dalgaard <pdalgd at gmail.com>
>>>>>     on Mon, 15 May 2017 16:28:42 +0200 writes:
    >> I think Herv?'s idea was just that if switch can evaluate
arguments selectively, so can stopifnot(). But switch() is .Primitive, so does
it from C.

    > if he just meant that, then "yes, of course" (but not so
interesting).

    >> I think it is almost a no-brainer to implement a sequential
stopifnot if dropping to C code is allowed. In R it gets trickier, but how about
this:

    > Something like this, yes, that's close to what Serguei Sokol had
proposed
    > (and of course I *do*  want to keep the current sophistication
    > of stopifnot(), so this is really too simple)

    >> Stopifnot <- function(...)
    >> {
    >> n <- length(match.call()) - 1
    >> for (i in 1:n)
    >> {
    >> nm <- as.name(paste0("..",i))
    >> if (!eval(nm)) stop("not all true")
    >> }
    >> }
    >> Stopifnot(2+2==4)
    >> Stopifnot(2+2==5, print("Hey!!!") == "Hey!!!")
    >> Stopifnot(2+2==4, print("Hey!!!") == "Hey!!!")
    >> Stopifnot(T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,T,F,T)


    >>> On 15 May 2017, at 15:37 , Martin Maechler <maechler at
stat.math.ethz.ch> wrote:
    >>> 
    >>> I'm still curious about Herv?'s idea on using  switch()
for the
    >>> issue.

    >> -- 
    >> Peter Dalgaard, Professor,
    >> Center for Statistics, Copenhagen Business School
    >> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
    >> Phone: (+45)38153501
    >> Office: A 4.23
    >> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com

    > ______________________________________________
    > R-devel at r-project.org mailing list
    > https://stat.ethz.ch/mailman/listinfo/r-devel