aes() should accept `!!!` at its first and second argument

[yutannihilation]

I feel this is a bit counter-intuitive. Is it possible to introduce some tweak to enable this?

library(ggplot2)

q <- quos(colour = Species)
aes(!!!q)
#> Error: Can't use `!!!` at top level

aes(x, y, !!!q)
#> Aesthetic mapping: 
#> * `x`      -> `x`
#> * `y`      -> `y`
#> * `colour` -> `Species`

Created on 2018-05-31 by the reprex package (v0.2.0).

[hadley]

@lionel- can you please take a look/think about this? (The problem is that aes() has x and y arguments)

[hadley]

Until we figure this out, there's a work around:

aes(,, !!!q)

[yutannihilation]

This isn't very clean, but I think we can introduce some tweak like this.

library(rlang)

aes <- function (x, y, ...) {
  x_expr <- quo_get_expr(enquo0(x))
  
  if (startsWith(expr_deparse(x_expr), "!!!")) {
    expr <- expr(quos(!!x_expr))
    exprs <- eval(expr, caller_env())
  } else {
    exprs <- enquos(x = x, y = y, ..., .ignore_empty = "all")
  }
  
  aes <- ggplot2:::new_aes(exprs, env = parent.frame())
  ggplot2:::rename_aes(aes)
}

aes(x, y, colour = Species)
#> Aesthetic mapping: 
#> * `x`      -> `x`
#> * `y`      -> `y`
#> * `colour` -> `Species`

q <- quos(colour = Species)
aes(!!!q)
#> Aesthetic mapping: 
#> * `colour` -> `Species`

^{Created on 2022-04-14 by the reprex package (v2.0.1)}

[teunbrand]

I'm not fluent in {rlang}, but I can improvise on a theme, in this case Yutannihilation's code above.
I've taken the idea above and made it slightly more flexible in terms of where the !!!q can be placed in aes().

library(rlang)

try_inject <- function(var, name, exprs, env = caller_env()) {

  expr <- quo_get_expr(var)
  if (is_missing(expr)) {
    return(exprs)
  }
  
  if (startsWith(expr_deparse(expr), "!!!")) {
    expr <- expr(quos(!!expr))
    expr <- eval(expr, env)
  } else {
    expr <- enquos(var, .ignore_empty = "all")
    names(expr) <- name
  }
  c(exprs, expr)
}

aes <- function(x, y, ...) {
  
  exprs <- enquos(..., .ignore_empty = "all")
  exprs <- try_inject(enquo0(x), "x", exprs)
  exprs <- try_inject(enquo0(y), "y", exprs)
  
  aes <- ggplot2:::new_aes(exprs, env = parent.frame())
  ggplot2:::rename_aes(aes)
  
}

q <- quos(colour = Species)

# New cases that now work
aes(x = Sepal.Width, !!!q)
#> Aesthetic mapping: 
#> * `x`      -> `Sepal.Width`
#> * `colour` -> `Species`
aes(y = Petal.Width, !!!q)
#> Aesthetic mapping: 
#> * `colour` -> `Species`
#> * `y`      -> `Petal.Width`

# These already worked with Yutannilation's code
aes(x = Sepal.Width, y = Petal.Width, !!!q)
#> Aesthetic mapping: 
#> * `colour` -> `Species`
#> * `x`      -> `Sepal.Width`
#> * `y`      -> `Petal.Width`
aes(!!!q)
#> Aesthetic mapping: 
#> * `colour` -> `Species`

^{Created on 2022-04-15 by the reprex package (v2.0.1)}

[yutannihilation]

Cool. You are already better at using rlang than I!

[lionel-]

Thanks @yutannihilation and @teunbrand! I've sent #4802 based on your implementations.

[yutannihilation]

Thanks!!