i_diamonds = interfacer::iface(
  carat = numeric ~ "the carat column",
  cut = enum(`Fair`, `Good`, `Very Good`, `Premium`, `Ideal`, .ordered = TRUE) ~
    "the cut column",
  color = enum(`D`, `E`, `F`, `G`, `H`, `I`, `J`, .ordered = TRUE) ~
    "the color column",
  clarity = enum(
    `I1`,
    `SI2`,
    `SI1`,
    `VS2`,
    `VS1`,
    `VVS2`,
    `VVS1`,
    `IF`,
    .ordered = TRUE
  ) ~
    "the clarity column",
  depth = numeric ~ "the depth column",
  table = numeric ~ "the table column",
  price = integer ~ "the price column",
  x = numeric ~ "the x column",
  y = numeric ~ "the y column",
  z = numeric ~ "the z column",
  .groups = FALSE
)

i_diamonds_data = interfacer::iface(
  carat = numeric ~ "the carat column",
  depth = numeric ~ "the depth column",
  table = numeric ~ "the table column",
  price = integer ~ "the price column",
  x = numeric ~ "the x column",
  y = numeric ~ "the y column",
  z = numeric ~ "the z column",
  .groups = FALSE
)

i_diamonds_cat = interfacer::iface(
  id = unique_id ~ "unique id",
  cut = enum(`Fair`, `Good`, `Very Good`, `Premium`, `Ideal`, .ordered = TRUE) ~
    "the cut column",
  color = enum(`D`, `E`, `F`, `G`, `H`, `I`, `J`, .ordered = TRUE) ~
    "the color column",
  clarity = enum(
    `I1`,
    `SI2`,
    `SI1`,
    `VS2`,
    `VS1`,
    `VVS2`,
    `VVS1`,
    `IF`,
    .ordered = TRUE
  ) ~
    "the clarity column",
  data = list(i_diamonds_data) ~
    "A nested data column must be specified as a list",
  .groups = FALSE
)

nested_diamonds = ggplot2::diamonds %>%
  tidyr::nest(data = c(-cut, -color, -clarity)) %>%
  dplyr::mutate(id = dplyr::row_number())

i_iris = interfacer::iface(
  Sepal.Length = numeric ~ "the Sepal.Length column",
  Sepal.Width = numeric ~ "the Sepal.Width column",
  Petal.Length = numeric ~ "the Petal.Length column",
  Petal.Width = numeric ~ "the Petal.Width column",
  Species = enum(`setosa`, `versicolor`, `virginica`) ~ "the Species column",
  .groups = NULL,
  .default = iris
)