Generalizing variable names for an RMarkdown Report

I want to make it easier (make fewer edits) in an RMarkdown report creation. For example, let's say I am investigating mtcars. My current workflow is to create a summary statistic for miles per gallon (mpg).

library(tidyverse)
library(rstatix)


df <- mtcars %>% get_summary_stats(mpg, type = "mean_sd")

mtcars <- mtcars %>% mutate(division_construct = case_when(
  mpg< 7.5 ~ "Low",
  between(mpg,7.5, 11.50) ~ "Below Average",
  between(mpg,11.501, 15.75) ~ "Above Average",
  mpg> 15.75 ~ "High",
  TRUE ~ "Error"))

Now let's say I want another column name, I have to manually make edits. Instead,
I want to do something like this:

var <- "mpg"

df <- mtcars %>% get_summary_stats(var, type = "mean_sd")

mtcars <- mtcars %>% mutate(division_construct = case_when(
  var < 7.5 ~ "Low",
  between(var,7.5, 11.50) ~ "Below Average",
  between(var,11.501, 15.75) ~ "Above Average",
  var > 15.75 ~ "High",
  TRUE ~ "Error"))

When I try to run the code, I get the following error:

Error in `mutate()`:
ℹ In argument: `division_construct = case_when(...)`.
Caused by error in `case_when()`:
! Failed to evaluate the left-hand side of formula 2.
Caused by error in `between()`:
! Can't combine `x` <character> and `left` <double>.

I think the error is because var is essentially a string and not a column name.

You may want to wrap the code in a function:

library(dplyr)

my_function <- function(var){
  df1 <-
    mtcars |>  
    mutate(division_construct = case_when(
      {{var}} < 7.5 ~ "Low",
      between( {{var}}, 7.5, 11.50) ~ "Below Average",
      between( {{var}}, 11.501, 15.75) ~ "Above Average",
      {{var}} > 15.75 ~ "High",
      TRUE ~ "Error"))
  return(df1)
}


my_function(var = mpg)[1:10, c("mpg", "division_construct")]
#>                    mpg division_construct
#> Mazda RX4         21.0               High
#> Mazda RX4 Wag     21.0               High
#> Datsun 710        22.8               High
#> Hornet 4 Drive    21.4               High
#> Hornet Sportabout 18.7               High
#> Valiant           18.1               High
#> Duster 360        14.3      Above Average
#> Merc 240D         24.4               High
#> Merc 230          22.8               High
#> Merc 280          19.2               High

^{Created on 2023-06-19 with reprex v2.0.2}