[Rd] New pipe operator

Hiroaki Yutani yut@n|@|n| @end|ng |rom gm@||@com
Fri Dec 4 14:13:46 CET 2020

>  Error: function '::' not supported in RHS call of a pipe

To me, this error looks much more friendly than magrittr's error.
Some of them got too used to specify functions without (). This
is OK until they use `::`, but when they need to use it, it takes
hours to figure out why

mtcars %>% base::head
#> Error in .::base : unused argument (head)

won't work but

mtcars %>% head

works. I think this is a too harsh lesson for ordinary R users to
learn `::` is a function. I've been wanting for magrittr to drop the
support for a function name without () to avoid this confusion,
so I would very much welcome the new pipe operator's behavior.
Thank you all the developers who implemented this!

Hiroaki Yutani

2020年12月4日(金) 20:51 Duncan Murdoch <murdoch.duncan using gmail.com>:
> Just saw this on the R-devel news:
> R now provides a simple native pipe syntax ‘|>’ as well as a shorthand
> notation for creating functions, e.g. ‘\(x) x + 1’ is parsed as
> ‘function(x) x + 1’. The pipe implementation as a syntax transformation
> was motivated by suggestions from Jim Hester and Lionel Henry. These
> features are experimental and may change prior to release.
> This is a good addition; by using "|>" instead of "%>%" there should be
> a chance to get operator precedence right.  That said, the ?Syntax help
> topic hasn't been updated, so I'm not sure where it fits in.
> There are some choices that take a little getting used to:
>  > mtcars |> head
> Error: The pipe operator requires a function call or an anonymous
> function expression as RHS
> (I need to say mtcars |> head() instead.)  This sometimes leads to error
> messages that are somewhat confusing:
>  > mtcars |> magrittr::debug_pipe |> head
> Error: function '::' not supported in RHS call of a pipe
> but
> mtcars |> magrittr::debug_pipe() |> head()
> works.
> Overall, I think this is a great addition, though it's going to be
> disruptive for a while.
> Duncan Murdoch
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