Using glue() with pipes - double printing

[lmeninato]

So usually in a pipe we use "." to not pass the left-hand side of the pipe to the first parameter.
For instance:

1:5 %>% c(1:3, . , 1:3)
 # [1] 1 2 3 1 2 3 4 5 1 2 3

But it doesn't seem to work properly with glue:

"bob" %>% glue("hello {.}")
 # [1] bobhello bob
# I'd expect "hello bob" ...

I'm sure there's a simple fix/workaround out there, but I couldn't find anything online regarding this issue. The pipe is pretty central to the tidyverse, but I understand if the glue wasn't meant to be used with "unnamed" variables (such as the pipe's (.)), so the solution might just be some documentation/awareness around this, rather than changing glue to work with the above issue.

Using R 3.6.2 and glue 1.4.2

[lmeninato]

Actually looks like this more of an issue with how the pipe handles using the placeholder (.) when it appears in a nested expression.

It is straightforward to use the placeholder several times in a right-hand side expression. However, when the placeholder only appears in a nested expressions magrittr will still apply the first-argument rule. The reason is that in most cases this results more clean code.
...
The behavior can be overruled by enclosing the right-hand side in braces:

Magrittr docs

We can actually solve the problem by just adding brackets around the glue command in the pipe:

"bob" %>% 
  {glue("hello {.}")}
# [1] hello bob

Would you guys be interested in a pull request mentioning this in the documentation? Might not be necessary since it's referenced indirectly in the Magrittr documentation.

[jimhester]

Sure adding an example to the glue documentation about this seems worthwhile.