Try this :
library(dplyr)
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
library(magrittr)
df = data.frame(
var1=c(1,3,5),
var2=c(3,2,1),
var3=c(10,2,2)
)
myfunc <- function(e){
df %>%
mutate(vars = {{e}})
}
myfunc(var1+var2-var3)
#> var1 var2 var3 vars
#> 1 1 3 10 -6
#> 2 3 2 2 3
#> 3 5 1 2 4
Created on 2021-08-10 by the reprex package (v2.0.0)