This is a wrapper around rmarkdown::render() that enforces the "reprex"
mentality. Here's a simplified version of what happens:
callr::r(
function(input) {
rmarkdown::render(input, envir = globalenv(), encoding = "UTF-8")
},
args = list(input = input),
spinner = is_interactive(),
stdout = std_file, stderr = std_file
)Key features to note
rmarkdown::render() is executed in a new R session, by using
callr::r(). The goal is to eliminate the leakage of objects, attached
packages, and other aspects of session state from the current session into
the rendering session. Also, the system and user-level .Rprofiles are
ignored.
Code is evaluated in the globalenv() of this new R session, which means
that method dispatch works the way most people expect it to.
The input file is assumed to be UTF-8, which is a knitr requirement as of v1.24.
If the YAML frontmatter includes std_err_out: TRUE, standard output and
error of the rendering R session are captured in std_file, which is
then injected into the rendered result.
reprex_render() is designed to work with the reprex_document() output
format, typically through a call to reprex(). reprex_render() may work
with other R Markdown output formats, but it is not well-tested.
reprex_render(input, html_preview = NULL, encoding = "UTF-8")The input file to be rendered. This can be a .R script or a
.Rmd R Markdown document.
Logical. Whether to show rendered output in a viewer
(RStudio or browser). Always FALSE in a noninteractive session. Read more
about opt().
The encoding of the input file. Note that the only acceptable value is "UTF-8", which is required by knitr as of v1.24. This is exposed as an argument purely for technical convenience, relating to the "Knit" button in the RStudio IDE.
The output of rmarkdown::render() is passed through, i.e. the path
of the output file.
if (FALSE) { # \dontrun{
reprex_render("input.Rmd")
} # }