Why is plotly() and enquo + !! in conflict?

Question

I am writing a function that uses plot_ly for a pieplot. The tilde (~) within argument labels = ~ is in conflict with the unquote operator !!. Is there a solution for this problem?

pieplotr <- function (df, Property){

Property_Name <- enquo(Property)

Pie <- plot_ly(df,
              labels = ~!!Property_Name,
              type = "pie")

return(Pie)

}

Toy_dataframe <- data.frame(
                 Sex = c("Male", "Female", "Female", "Male", "Male","NA"),
                 Height = c(12,11,7,3,9,NA),
                 Name = c("John", "Dora", "Dora","Dora", "Anna", "John"),
                 Last = c("Henry", "Paul", "House", "Houze", "Henry", "Bill"),
                 Location = c("Chicago", "Chicago", "Portland", "NYC", "NYC", "NYC"),
                 stringsAsFactors = TRUE)

e.g.

pieplotr(df = Toy_dataframe,
          Property = Name)

I expect to return a pieplot, but I am getting the following error message:

Error in as.list.environment(x, all.names = TRUE) :
object 'Name' not found

Answer 1

We can evaluate after creating creating an expression

pieplotr <- function (df, Property){

Property_Name <- rlang::enquo(Property)
rlang::eval_tidy(
    rlang::quo_squash(quo(
    plot_ly(df, labels = ~!!Property_Name,  type = "pie")
    )))


} 




pieplotr(df = Toy_dataframe, Property = Name)

-output

---

Or remove the ~!!

pieplotr <- function (df, Property){

Property_Name <- rlang::enquo(Property)

    plot_ly(df, labels = Property_Name,  type = "pie")



}

pieplotr(df = Toy_dataframe, Property = Name)

Answer 2

An alternative solution is to avoid non-standard-evaluation / quasiquoation entirely and simply modify how you are calling the function

pieplotr <- function (df, Property) {
    plot_ly(df, labels = Property, type = "pie")
}

pieplotr( Toy_dataframe, ~Name )    # Notice the ~

The reason this works here is because the plotly universe uses formulas (defined via ~) to pass around information about variables. Tidyverse uses unevaluated expressions instead of formulas, which is the reason for needing enquo(), etc.