Hello,
R is a functional language, pipes are not. There are even higher order
functions such as [1] and [2].
Besides, packages are part of R, R couldn't live without them. I find
pipes a good idea but I also find it better not to have them as part of
base R. If you want to use them, load a package, if you don't, don't.
This simple.
As for your example, compose, there is a StackOverflow question on it.
See this answer [3].
[1] https://stat.ethz.ch/R-manual/R-devel/library/base/html/funprog.html
[2] https://stat.ethz.ch/R-manual/R-devel/library/base/html/Recall.html
[3] https://stackoverflow.com/a/52465956/8245406
Hope this helps,
Rui Barradas
Às 16:48 de 05/10/19, Ant F escreveu:
Hi John,
Thanks, but the Bizzaro pipe comes with many flaws though :
* It's not a single operator
* It has a different precedence
* It cannot be used in a subcall
* The variable assigned to must be on the right
* It doesn't trigger indentation when going to the line
* It creates/overwrite a `.` variable in the worksace.
And it doesn't deal gracefully with some lazy evaluation edge cases such as
:
compose <- function(f, g) { function(x) g(f(x)) }
plus1 <- function(x) x + 1
plus2 <- plus1 %.% compose(.,plus1)
plus2(5)
#> [1] 7
plus1 ->.; compose(.,plus1) -> .; . -> plus2
plus2(5)
#> Error: C stack usage 15923776 is too close to the limit
What I propose on the other hand can always substitute any existing proper
pipe in their standard feature, as long as the dot is made explicit.
Best regards,
Antoine
Le sam. 5 oct. 2019 à 16:59, John Mount <jmo...@win-vector.com> a écrit :
Actually, base R already has a pipe fairly close to the one you describe:
->.;
iris ->.; head(.) ->.; dim(.)
# [1] 6 5
I've called it the Bizarro pipe (
http://www.win-vector.com/blog/2016/12/magrittrs-doppelganger/ ), and for
some reason we chickened out and didn't spend time on it in the dot pipe
paper ( https://journal.r-project.org/archive/2018/RJ-2018-042/index.html
).
For documentation Bizarro pipe has the advantage that one can work out how
it works from the application itself, with out reference to a defining
function.
On Oct 5, 2019, at 7:34 AM, Ant F <antoine.fa...@gmail.com> wrote:
Dear R-devel,
The most popular piping operator sits in the package `magrittr` and is used
by a huge amount of users, and imported /reexported by more and more
packages too.
Many workflows don't even make much sense without pipes nowadays, so the
examples in the doc will use pipes, as do the README, vignettes etc. I
believe base R could have a piping operator so packages can use a pipe in
their code or doc and stay dependency free.
I don't suggest an operator based on complex heuristics, instead I suggest
a very simple and fast one (>10 times than magrittr in my tests) :
`%.%` <- function (e1, e2) {
eval(substitute(e2), envir = list(. = e1), enclos = parent.frame())
}
iris %.% head(.) %.% dim(.)
#> [1] 6 5
The difference with magrittr is that the dots must all be explicit (which
sits with the choice of the name), and that special magrittr features such
as assignment in place and building functions with `. %>% head() %>% dim()`
are not supported.
Edge cases are not surprising:
```
x <- "a"
x %.% quote(.)
#> .
x %.% substitute(.)
#> [1] "a"
f1 <- function(y) function() eval(quote(y))
f2 <- x %.% f1(.)
f2()
#> [1] "a"
```
Looking forward for your thoughts on this,
Antoine
[[alternative HTML version deleted]]
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
---------------
John Mount
http://www.win-vector.com/
Our book: Practical Data Science with R
https://www.manning.com/books/practical-data-science-with-r-second-edition
<http://www.manning.com/zumel/>
[[alternative HTML version deleted]]
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
