Apply s3_key_exists recursively to S3 keys in a list

This function raises an error as soon as any S3 key does not exist.

Usage

s3_key_exists_list(
  l,
  predicate = function(l, name) is.character(l),
  transform = identity,
  verbose = FALSE
)

Arguments

l

List.

predicate

A function taking two arguments l (an element of a list) and name (currently defunct). If this function returns TRUE, transform is applied on this element of the list.

transform

A function taking one argument l (an element of a list). This function should return a character representing a potential S3 key. This character is then passed to s3_key_exists.

verbose

If TRUE, print more output.