use knit_print methods for inline R #1179
Description
Update: On further inspection, the below is a feature request, not a bug report, I think.
Reworded accordingly.
It would be great if inline dynamic R code would respect the knitr::knit_print() method, which in turn can have special behavior for inline=TRUE.
I don't think it currently does.
Here's a reprex:
#' Reprex
#' @inheritParams knitr::knit_print
#' @param inline logical flag, whether print method is used from inside inline or a chunk.
#' @export
#' @section Let's test the print method:
#'
#' Setting things up:
#' ```{r}
#' library(knitr)
#' x <- structure("I'm the default printing method.", class = "foo")
#' ```
#'
#' Here's the chunk output:
#'
#' ```{r}
#' x
#' ```
#'
#' And inline with manual invocation: `r knitr::knit_print(x, inline = TRUE)`.
#'
#' And inline without manual invocation: `r x`.
knit_print.foo <- function(x, inline = FALSE, ...) {
out <- ifelse(inline, "I'm inline R output", "I'm an R chunk output")
knitr::asis_output(out)
}And the resulting knit_print.foo.Rd:
% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/reprex.R
\name{knit_print.foo}
\alias{knit_print.foo}
\title{Reprex}
\usage{
\method{knit_print}{foo}(x, inline = FALSE, ...)
}
\arguments{
\item{x}{An R object to be printed}
\item{inline}{logical flag, whether print method is used from inside inline or a chunk.}
\item{...}{Additional arguments passed to the S3 method. Currently ignored,
except two optional arguments \code{options} and \code{inline}; see
the references below.}
}
\description{
Reprex
}
\section{Let's test the print method}{
Setting things up:\if{html}{\out{<div class="r">}}\preformatted{library(knitr)
x <- structure("I'm the default printing method.", class = "foo")
}\if{html}{\out{</div>}}
Here's the chunk output:\if{html}{\out{<div class="r">}}\preformatted{x
}\if{html}{\out{</div>}}
I'm an R chunk output
And inline with manual invocation: I'm inline R output.
And inline without manual invocation: I'm the default printing method..
}
As can be seen in the above *.Rd output, all works fine, except for the inline R code.
Here, roxygen2 seems to fall back to the print() generic, not knit_print() method.
sessioninfo::session_info():
─ Session info ─────────────────────────────────────────────────────────────────────────────────────
setting value
version R version 4.0.3 (2020-10-10)
os macOS 11.1
system x86_64, darwin17.0
ui X11
language en_US.UTF-8 git
collate en_US.UTF-8
ctype en_US.UTF-8
tz Europe/Berlin
date 2021-01-08
─ Packages ─────────────────────────────────────────────────────────────────────────────────────────
! package * version date lib source
assertthat 0.2.1 2019-03-21 [1] CRAN (R 4.0.2)
backports 1.2.1 2020-12-09 [1] CRAN (R 4.0.2)
P biblids * 0.0.0.9000 2020-12-11 [?] Github (subugoe/biblids@d44010e)
callr 3.5.1 2020-10-13 [1] CRAN (R 4.0.2)
checkmate 2.0.0 2020-02-06 [1] CRAN (R 4.0.2)
cli 2.2.0 2020-11-20 [1] CRAN (R 4.0.2)
commonmark 1.7 2018-12-01 [1] CRAN (R 4.0.2)
crayon 1.3.4 2017-09-16 [1] CRAN (R 4.0.2)
desc 1.2.0 2018-05-01 [1] CRAN (R 4.0.2)
devtools * 2.3.2 2020-09-18 [1] CRAN (R 4.0.2)
digest 0.6.27 2020-10-24 [1] CRAN (R 4.0.2)
ellipsis 0.3.1 2020-05-15 [1] CRAN (R 4.0.2)
evaluate 0.14 2019-05-28 [1] CRAN (R 4.0.1)
fansi 0.4.1 2020-01-08 [1] CRAN (R 4.0.2)
fastmap 1.0.1 2019-10-08 [1] CRAN (R 4.0.2)
fs 1.5.0 2020-07-31 [1] CRAN (R 4.0.2)
glue 1.4.2 2020-08-27 [1] CRAN (R 4.0.2)
htmltools 0.5.0.9003 2020-12-03 [1] Github (rstudio/htmltools@d18bd8e)
httpuv 1.5.4 2020-06-06 [1] CRAN (R 4.0.2)
httr 1.4.2 2020-07-20 [1] CRAN (R 4.0.2)
jsonlite 1.7.2 2020-12-09 [1] CRAN (R 4.0.2)
knitr * 1.30 2020-09-22 [1] CRAN (R 4.0.2)
later 1.1.0.1 2020-06-05 [1] CRAN (R 4.0.2)
lifecycle 0.2.0 2020-03-06 [1] CRAN (R 4.0.2)
magrittr 2.0.1 2020-11-17 [1] CRAN (R 4.0.2)
memoise 1.1.0 2017-04-21 [1] CRAN (R 4.0.2)
mime 0.9 2020-02-04 [1] CRAN (R 4.0.2)
muggle * 0.1.0-2 2020-12-21 [1] Github (subugoe/muggle@756b353)
pkgbuild 1.2.0 2020-12-15 [1] CRAN (R 4.0.2)
pkgload 1.1.0 2020-05-29 [1] CRAN (R 4.0.2)
prettyunits 1.1.1 2020-01-24 [1] CRAN (R 4.0.2)
processx 3.4.5 2020-11-30 [1] CRAN (R 4.0.2)
promises 1.1.1.9001 2020-12-11 [1] Github (rstudio/promises@bbadb3d)
ps 1.5.0 2020-12-05 [1] CRAN (R 4.0.2)
purrr 0.3.4 2020-04-17 [1] CRAN (R 4.0.2)
R6 2.5.0 2020-10-28 [1] CRAN (R 4.0.2)
Rcpp 1.0.5 2020-07-06 [1] CRAN (R 4.0.2)
remotes 2.2.0 2020-07-21 [1] CRAN (R 4.0.2)
reprex 0.3.0 2019-05-16 [1] CRAN (R 4.0.2)
rlang 0.4.10.9000 2021-01-05 [1] Github (r-lib/rlang@b8d14c3)
roxygen2 7.1.1 2020-06-27 [1] CRAN (R 4.0.2)
rprojroot 2.0.2 2020-11-15 [1] CRAN (R 4.0.2)
rstudioapi 0.13 2020-11-12 [1] CRAN (R 4.0.2)
sessioninfo 1.1.1 2018-11-05 [1] CRAN (R 4.0.2)
shiny 1.5.0.9006 2020-12-30 [1] Github (rstudio/shiny@2590cf3)
stringi 1.5.3 2020-09-09 [1] CRAN (R 4.0.2)
stringr 1.4.0 2019-02-10 [1] CRAN (R 4.0.2)
testthat * 3.0.1 2020-12-17 [1] CRAN (R 4.0.2)
usethis * 2.0.0 2020-12-10 [1] CRAN (R 4.0.2)
vctrs 0.3.6 2020-12-17 [1] CRAN (R 4.0.2)
withr 2.3.0 2020-09-22 [1] CRAN (R 4.0.2)
xfun 0.19 2020-10-30 [1] CRAN (R 4.0.2)
xml2 1.3.2 2020-04-23 [1] CRAN (R 4.0.2)
xtable 1.8-4 2019-04-21 [1] CRAN (R 4.0.2)
Perhaps this is because roxygen2 is using it's own inline rendering engine?
The docs maybe suggest this:
The value of the R expression is converted to a character string, with
paste(collapse = "\n").
So you don’t need explicitly convert to a character value, numeric values or any R object with anas.character()S3 method is fine.
Also, you can insert multiple lines by returning a character vector.
If you want to run R code without inserting any output, return an empty string or NULL.
However, R chunks do seem rely on knitr.
Either way, it'd be great to use the knitr generic here.