>>>>> William Dunlap
>>>>> on Tue, 21 May 2019 12:11:45 -0700 writes:
> Letting a user supply the autoprint function would be nice also. In a way
> you can already do that, using addTaskCallback(), but that doesn't let you
> suppress the standard autoprinting.
> Having the default autoprinting do its own style of method dispatch
doesn't
> seem right.
I agree (if I understand correctly what you mean ... ;-)
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
> On Tue, May 21, 2019 at 10:50 AM Lionel Henry <lio...@rstudio.com> wrote:
>> 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 now vaguely remember.
OTOH, tests/reg-tests-2.R {the "output related" regression tests}
*did* have an explicit test to ensure that print() and
auto-print do the same thing for functions:
print.function <- function(x, ...) { str(x,...); invisible(x) }
print.function
f
rm(print.function)
## auto-printing and printing differed up to R 2.9.x
so this was not
"an undocumented consequence of an implementation detail" ..
but you are right that it has not been documented explicitly.
>> 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.
Thank you, Lionel; but I'm not convinced :
I'm pretty sure that all teaching and documentation about S and R
has suggested that print(f) and auto-printing should result in
the same output _ AFAIR also for S4 objects
[unless print() and show() methods were explicitly made to differ.. ? ]
>> 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
I'd rather we'd work towards the goal that auto printing
and print() should result in identical output :
1) for unclassed basic objects, i.e., what Bill meant with print.<storageMode>
where maybe print.<typeof> would be a slightly better name;
2) for S3 classed objects;
3) for S4 classed objects with no print() method (but possibly a show() one).
Adding an option for autoprinting would render R even less
strictly functional, depending on yet another powerful global option,
and typical R usage would become more different from
'R --vanilla' even more --- really not a good direction to go in my view.
AFAICS, the above goal would need changes only for case '1)'
Martin
>> > On 21 May 2019, at 13:38, William Dunlap via R-devel <
>> r-devel@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 <
>> maech...@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
>> >>
>> >
>> > [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-devel@r-project.org mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>>
> [[alternative HTML version deleted]]
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