R devel - Dec 2020 - [External] anonymous functions

I don't disagree in principle, but the reality is users want shortcuts
and as a result various packages, in particular tidyverse, have been
providing them. Mostly based on formulas, mostly with significant
issues since formulas weren't designed for this, and mostly
incompatible (tidyverse ones are compatible within tidyverse but not
with others). And of course none work in sapply or lapply. Providing a
shorthand in base may help to improve this. You don't have to use it
if you don't want to, and you can establish coding standards that
disallow it if you like.

Best,

luke

On Mon, 7 Dec 2020, Therneau, Terry M., Ph.D. via R-devel wrote:
> ?The shorthand form \(x) x + 1 is parsed as function(x) x + 1. It may be 
> helpful in making code containing simple function expressions more
readable.?
>
> Color me unimpressed.
> Over the decades I've seen several "who can write the shortest
code" threads:
> in Fortran, in C, in Splus, ...   The same old idea that "short"
is a synonym
> for either elegant, readable, or efficient is now being recylced in the 
> tidyverse.   The truth is that "short" is actually an antonym for
all of
> these things, at least for anyone else reading the code; or for the
original
> coder 30-60 minutes after the "clever" lines were written. 
Minimal use of
> the spacebar and/or the return key isn't usually held up as a goal, but
> creeps into many practiioner's code as well.
>
> People are excited by replacing "function(" with "\("? 
Really?   Are people
> typing code with their thumbs?
> I am ambivalent about pipes: I think it is a great concept, but too many of
> my colleagues think that using pipes = no need for any comments.
>
> As time goes on, I find my goal is to make my code less compact and more 
> readable.  Every bug fix or new feature in the survival package now adds
more
> lines of comments or other documentation than lines of code.  If I have to 
> puzzle out what a line does, what about the poor sod who inherits the 
> maintainance?
>
>
>
-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:   luke-tierney at uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu

Luke,
 ? Mostly an aside.? I think that pipes are a good addition, and it is clear
that you and
other R-core thought through many of the details.?? Congratulations on what
appears to be
solid work. I've used Unix since '79, so it is almost guarranteed that I
like the basic
idiom, and I expect to make use of it.? Users who think that pipes -- or any
other code --
is so clear that comments are superfluous is no reflection on R core, and also a
bit of a
hobby horse for me.

I am a bit bemused by the flood of change suggestions, before people have had a
chance to
fully exercise the new code. ? I'd suggest waiting several months, or a
year, before major
updates, straight up bugs excepted. ? The same advice holds when moving into a
new house.
One? experience with the survival package has been that most new ideas have been
implemented locally, and we run with them for half a year before submission to
CRAN.? I've
had a few "really great" modifications that, thankfully, were never
inflicted on the rest
of the R community.

Terry T.

On 12/7/20 11:26 AM, luke-tierney at uiowa.edu wrote:
> I don't disagree in principle, but the reality is users want shortcuts
> and as a result various packages, in particular tidyverse, have been
> providing them. Mostly based on formulas, mostly with significant
> issues since formulas weren't designed for this, and mostly
> incompatible (tidyverse ones are compatible within tidyverse but not
> with others). And of course none work in sapply or lapply. Providing a
> shorthand in base may help to improve this. You don't have to use it
> if you don't want to, and you can establish coding standards that
> disallow it if you like.
>
> Best,
>
> luke
>
> On Mon, 7 Dec 2020, Therneau, Terry M., Ph.D. via R-devel wrote:
>
>> ?The shorthand form \(x) x + 1 is parsed as function(x) x + 1. It may
be helpful in
>> making code containing simple function expressions more readable.?
>>
>> Color me unimpressed.
>> Over the decades I've seen several "who can write the shortest
code" threads: in
>> Fortran, in C, in Splus, ...?? The same old idea that "short"
is a synonym for either
>> elegant, readable, or efficient is now being recylced in the
tidyverse.?? The truth is
>> that "short" is actually an antonym for all of these things,
at least for anyone else
>> reading the code; or for the original coder 30-60 minutes after the
"clever" lines were
>> written. Minimal use of the spacebar and/or the return key isn't
usually held up as a
>> goal, but creeps into many practiioner's code as well.
>>
>> People are excited by replacing "function(" with
"\("? Really??? Are people typing code
>> with their thumbs?
>> I am ambivalent about pipes: I think it is a great concept, but too
many of my
>> colleagues think that using pipes = no need for any comments.
>>
>> As time goes on, I find my goal is to make my code less compact and
more readable.?
>> Every bug fix or new feature in the survival package now adds more
lines of comments or
>> other documentation than lines of code.? If I have to puzzle out what a
line does, what
>> about the poor sod who inherits the maintainance?
>>
>>
>>
>

	[[alternative HTML version deleted]]

On 07/12/2020 12:26 p.m., luke-tierney at uiowa.edu
wrote:
> I don't disagree in principle, but the reality is users want shortcuts
> and as a result various packages, in particular tidyverse, have been
> providing them. Mostly based on formulas, mostly with significant
> issues since formulas weren't designed for this, and mostly
> incompatible (tidyverse ones are compatible within tidyverse but not
> with others). And of course none work in sapply or lapply. Providing a
> shorthand in base may help to improve this. You don't have to use it
> if you don't want to, and you can establish coding standards that
> disallow it if you like.
Here's a suggestion to let people define their own shorthands and work 
with the current |> definition.

Define "as.call" as an S3 generic, with a default definition something
like

as.call.default <- function(x, f, ...) f(x, ...)

so one could use

  x |> as.call(mean)

to get the same result as

  x |> mean()

or (if working in the tidyverse)

  x |> as.call(~ .x + 1)

to use a method to be provided by rlang or purrr to convert their 
shorthand into a call that the pipe can work with.

We already have the generic as.function, which could be used internally 
by lapply and sapply for the same sort of purpose.  tidyverse has 
rlang::as_function, so they could pretty easily add methods for 
as.function if they wanted to allow people to use their shorthand in 
*apply functions.

Duncan Murdoch

On Mon, Dec 7, 2020 at 12:34 PM <luke-tierney at uiowa.edu>
wrote:
> I don't disagree in principle, but the reality is users want shortcuts
> and as a result various packages, in particular tidyverse, have been
> providing them. Mostly based on formulas, mostly with significant
> issues since formulas weren't designed for this, and mostly
> incompatible (tidyverse ones are compatible within tidyverse but not
> with others). And of course none work in sapply or lapply.
The formulas as functions in the gsubfn package work with nearly any function
including sapply and lapply.

  library(gsubfn)
  fn$lapply(1:3, ~ x + 1)
  ## [1] 2 3 4