s3.md
In rlang: Functions for Base Types and Core R and 'Tidyverse' Features

as_box_if() ensures boxed value if predicate returns TRUE

Code
  (expect_error(as_box_if(NULL, ~10)))
Output
  <error/rlang_error>
  Error in `.p()`:
  ! Predicate functions must return a single `TRUE` or `FALSE`, not the number 10
Code
  (expect_error(as_box_if(NULL, ~ c(TRUE, FALSE))))
Output
  <error/rlang_error>
  Error in `.p()`:
  ! Predicate functions must return a single `TRUE` or `FALSE`, not a logical vector