qq_show() helps examining injected expressions
inside a function. This is useful for learning about injection and
for debugging injection code.
An expression involving injection operators.
qq_show() shows the intermediary expression before it is
evaluated by R:
list2(!!!1:3)
#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 2
#>
#> [[3]]
#> [1] 3
qq_show(list2(!!!1:3))
#> list2(1L, 2L, 3L)
It is especially useful inside functions to reveal what an injected expression looks like:
my_mean <- function(data, var) {
qq_show(data %>% dplyr::summarise(mean({{ var }})))
}mtcars %>% my_mean(cyl)
#> data %>% dplyr::summarise(mean(^cyl))
Injecting with !!, !!!, and glue syntax