Lots of object do not display anything: in this case "formattable"

[jankatins]

#devtools::install_github("renkun-ken/formattable")
library(formattable)

df <- data.frame(
  id = 1:10,
  name = c("Bob", "Ashley", "James", "David", "Jenny", 
    "Hans", "Leo", "John", "Emily", "Lee"), 
  age = c(28, 27, 30, 28, 29, 29, 27, 27, 31, 30),
  grade = c("C", "A", "A", "C", "B", "B", "B", "A", "C", "C"),
  test1_score = c(8.9, 9.5, 9.6, 8.9, 9.1, 9.3, 9.3, 9.9, 8.5, 8.6),
  test2_score = c(9.1, 9.1, 9.2, 9.1, 8.9, 8.5, 9.2, 9.3, 9.1, 8.8),
  final_score = c(9, 9.3, 9.4, 9, 9, 8.9, 9.25, 9.6, 8.8, 8.7),
  registered = c(TRUE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE),
  stringsAsFactors = FALSE)

f <- formattable(df, list(
  age = color_tile("white", "orange"),
  grade = formatter("span",
    style = x ~ ifelse(x == "A", style(color = "green", font.weight = "bold"), NA)),
  test1_score = normalize_bar("pink", 0.2),
  test2_score = normalize_bar("pink", 0.2),
  final_score = formatter("span",
    style = x ~ style(color = ifelse(rank(-x) <= 3, "green", "gray")),
    x ~ sprintf("%.2f (rank: %02d)", x, rank(-x))),
  registered = formatter("span", 
    style = x ~ style(color = ifelse(x, "green", "red")),
    x ~ icontext(ifelse(x, "ok", "remove"), ifelse(x, "Yes", "No")))
))

f # does not display anything
class(f) # displays "formattable" "data.frame"
print(f) # nothing

I think this happens when print(f) does not print anything and we don't have anything to make a rich display...

In rstudio, the f already triggers something, so we really should implement the same way rstudio handles this...

x = print(f)

this also triggers a display in rstudio and sets x:

> x = print(f)
> class(x)
[1] "formattable_widget" "htmlwidget" 

So it seems we should implement a repr_html.htmlwidget (and maybe repr_html.formattable? I haven't fully understand the knit_print.*() hierarchy/call chain in formattable yet) and also check that we have the same display mechanism as rstudio (do they have a way to deliver plots to the plot area?).

Regarding things we have no rich printing for: I've no clue how to reliably tell if we miss a repr_xxx.class_type (and tell the user that they should bug us or the package owner for such a method) or that the package author didn't want a visible output. If someone has a clue...

CC: @renkun-ken (owner of the formattable package)

[renkun-ken]

Thanks, @JanSchulz! I notice this too using formattable in the notebook and tries ggvis and it opens a new webpage to show the interactive plot.

[jankatins]

This is the knit_print method, which is

knit_print.htmlwidget <- function(x, ..., options = NULL) {
  knitr::knit_print(toHTML(x, standalone = FALSE, knitrOptions = options), options = options,  ...)
}

So if we want to set width/height we would have to construct a knitrOption structure so that https://github.com/ramnathv/htmlwidgets/blob/3a2e3120ef59260afe9f6e5be08d1cd7612ba903/R/sizing.R#L207-L216 does the right thing...

[kcy1019]

Thanks @JanSchulz !
In IRdisplay_0.4.9000

x = formattable(...)
y = print(x)
y

worked perfectly :)
(Howerver, as you mentioned, just calling print(x) directly w/o variable y did not show anything)