[Rd] print.<strorageMode>() not called when autoprinting

[Lionel Henry]

FWIW it was the intention of the patch to make printing of unclassed
functions consistent with other base types. This was documented in the
"patch 3" section:

https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17398

I think we need a general way to customise auto-printing for base types
and even classed objects as that'd be useful for both users and IDEs.

However S3 dispatch may not be optimal for this because it essentially
requires polluting the global environment with print methods. Maybe
it'd make sense to add getOption("autoprint") which should be set to
a user- or environment- supplied function. That function would do the
dispatch. I'd be happy to send a patch for this, if it makes sense.

Best,
Lionel


> On 21 May 2019, at 13:38, William Dunlap via R-devel <r-devel using r-project.org> wrote:
> 
> It also is a problem with storage.modes "integer" and "complex":
> 
> 3.6.0> print.integer <- function(x,...) "integer vector"
>                3.6.0> 1:10
> [1]  1  2  3  4  5  6  7  8  9 10
> 3.6.0> print(1:10)
> [1] "integer vector"
> 3.6.0>
> 3.6.0> print.complex <- function(x, ...) "complex vector"
> 3.6.0> 1+2i
> [1] 1+2i
> 3.6.0> print(1+2i)
> [1] "complex vector"
> 
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
> 
> 
> On Tue, May 21, 2019 at 9:31 AM Martin Maechler <maechler using stat.math.ethz.ch>
> wrote:
> 
>>>>>>> William Dunlap via R-devel
>>>>>>>    on Thu, 16 May 2019 11:56:45 -0700 writes:
>> 
>>> In R-3.6.0 autoprinting was changed so that print methods for the
>> storage
>>> modes are not called when there is no explicit class attribute.
>> E.g.,
>> 
>>> % R-3.6.0 --vanilla --quiet
>>>> print.function <- function(x, ...) { cat("Function with argument
>> list ");
>>> cat(sep="\n    ", head(deparse(args(x)), -1)); invisible(x) }
>>>> f <- function(x, ...) { sum( x * seq_along(x) ) }
>>>> f
>>> function(x, ...) { sum( x * seq_along(x) ) }
>>>> print(f)
>>> Function with argument list function (x, ...)
>> 
>>> Previous to R-3.6.0 autoprinting did call such methods
>>> % R-3.5.3 --vanilla --quiet
>>>> print.function <- function(x, ...) { cat("Function with argument
>> list ");
>>> cat(sep="\n    ", head(deparse(args(x)), -1)); invisible(x) }
>>>> f <- function(x, ...) { sum( x * seq_along(x) ) }
>>>> f
>>> Function with argument list function (x, ...)
>>>> print(f)
>>> Function with argument list function (x, ...)
>> 
>>> Was this intentional?
>> 
>> No, it was not.  ... and I've been the one committing the wrong change.
>> 
>> ... Related to the NEWS entries which start
>> 
>>     "Changes in print.*() ...."
>> 
>> Thank you Bill, for reporting....
>> 
>> It's amazing this has not been detected earlier by anybody.
>> 
>> I think it is *only* for functions, not general
>> print.<storagemode>() as you were suggesting - right?
>> 
>> Martin
>> 
> 
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