[Rd] eval(parse()) within mutate() returning same value for all rows

[Mateo Obregón]

Hi all-

Looking through stackoverflow for R string combining examples, I found the 
following from 3 years ago:

<https://stackoverflow.com/questions/63881854/how-to-format-strings-using-values-from-other-column-in-r>

The top answer suggests to use eval(parse(sprintf())). I tried the suggestion 
and it did not return the expected combines strings. I thought that this might 
be an issue with some leftover values being reused, so I explicitly eval() 
with a new.env():

> library(dplyr)
> df <- tibble(words=c("%s plus %s equals %s"), 
args=c("1,1,2","2,2,4","3,3,6"))
> df |> mutate(combined = eval(parse(text=sprintf("sprintf('%s', %s)", words, 
args)), envir=new.env()))

# A tibble: 3 × 3
  words                args  combined         
  <chr>                <chr> <chr>            
1 %s plus %s equals %s 1,1,2 3 plus 3 equals 6
2 %s plus %s equals %s 2,2,4 3 plus 3 equals 6
3 %s plus %s equals %s 3,3,6 3 plus 3 equals 6

The `combined`  is not what I was expecting, as the same last eval() is 
returned for all three rows.
 
Am I missing something? What has changed in the past three years?

Mateo.
--  
Mateo Obregón