A glue transformer inspired by the "variables & values" f-string syntax in Python 3.8

vv_transformer.R

library(glue)

vv_transformer <- function(text, envir) {
  regex <- "=$"
  if (!grepl(regex, text)) {
    return(identity_transformer(text, envir))
  }
  text <- sub(regex, "", text)
  res <- identity_transformer(text, envir)
  n <- length(res)
  res <- glue_collapse(res, sep = ", ")
  if (n > 1) {
    res <- c("[", res, "]")
  }
  glue_collapse(c(text, " = ", res))
}

description <- "these awesome"
numbers <- c(90, 95, 80, 100)
average <- mean(numbers)
sum <- sum(numbers)

glue("For {description} {numbers=}, {average=}, {sum=}.", .transformer = vv_transformer)
#> For these awesome numbers = [90, 95, 80, 100], average = 91.25, sum = 365.

description <- "some random"
numbers <- sample(100, 4)
average <- mean(numbers)
sum <- sum(numbers)

glue("For {description} {numbers=}, {average=}, {sum=}.", .transformer = vv_transformer)
#> For some random numbers = [83, 5, 71, 68], average = 56.75, sum = 227.

a <- 3
b <- 5.6
glue("{a=}\n{b=}\n{a * 9 + b * 2=}", .transformer = vv_transformer)
#> a = 3
#> b = 5.6
#> a * 9 + b * 2 = 38.2

https://docs.python.org/3.8/whatsnew/3.8.html#f-strings-now-support-for-quick-and-easy-debugging