pander: Pandoc.brew – R documentation

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Pandoc.brew

Brew in pandoc format

Description

This function behaves just like brew except for the <%=...%> tags, where Pandoc.brew first translate the R object found between the tags to Pandoc's markdown before passing to the cat function.

Usage

Pandoc.brew(file = stdin(), output = stdout(), convert = FALSE,
  open = TRUE, graph.name, graph.dir, graph.hi.res = FALSE,
  text = NULL, envir = parent.frame(), append = FALSE, ...)

Arguments

`file`	file path of the brew template. As this is passed to `readLines`, `file` could be an URL too, but not over SSL (for that latter `RCurl` would be needed).
`output`	(optional) file path of the output file
`convert`	string: format of required output document (besides Pandoc's markdown). Pandoc is called if set via `Pandoc.convert` and the converted document could be also opened automatically (see below).
`open`	try to open converted document with operating system's default program
`graph.name`	character string (default to `%t` when `output` is set to `stdout` and `paste0(basename(output), '-%n')` otherwise) passed to `evals`. Besides `evals`'s possible tags `%i` is also available which would be replaced by the chunk number (and optionally an integer which would handle nested `brew` calls) and `%I` with the order of the current expression.
`graph.dir`	character string (default to `tempdir()` when `output` is set to `stdout` and `dirname(graph.name)` otherwise) passed to `evals`
`graph.hi.res`	render high resolution images of plots? Default is `FALSE` except for HTML output.
`text`	character vector (treated as the content of the `file`
`envir`	environment where to `brew` the template
`append`	should append or rather overwrite (default) the `output` markdown text file? Please note that this option only affects the markdown file and not the optionally created other formats.
`...`	additional parameters passed to `Pandoc.convert`

Details

This parser tries to be smart in some ways:

a block (R commands between the tags) could return any value at any part of the block and there are no restrictions about the number of returned R objects
plots and images are grabbed in the document, rendered to a png file and pander method would result in a Pandoc's markdown formatted image link (so the image would be shown/included in the exported document). The images are put in plots directory in current getwd() or to the specified output file's directory.
all warnings/messages and errors are recorded in the blocks and returned in the document as a footnote

Please see my Github page for details (http://rapporter.github.com/pander/#brew-to-pandoc) and examples (http://rapporter.github.com/pander/#examples).

Value

converted file name with full path if convert is set, none otherwise

Note

Only one of the input parameters (file or text) is to be used at once!

References

Jeffrey Horner (2011). _brew: Templating Framework for Report Generation._ https://cran.r-project.org/package=brew
John MacFarlane (2012): _Pandoc User's Guide_. http://johnmacfarlane.net/pandoc/README.html

Examples

## Not run: 
text <- paste('# Header', '',
  'What a lovely list:\n<%=as.list(runif(10))%>',
  'A wide table:\n<%=mtcars[1:3, ]%>',
  'And a nice chart:\n\n<%=plot(1:10)%>', sep = '\n')
Pandoc.brew(text = text)
Pandoc.brew(text = text, output = tempfile(), convert = 'html')
Pandoc.brew(text = text, output = tempfile(), convert = 'pdf')

## pi is awesome
Pandoc.brew(text='<%for (i in 1:5) {%>\n Pi has a lot (<%=i%>) of power: <%=pi^i%><%}%>')

## package bundled examples
Pandoc.brew(system.file('examples/minimal.brew', package='pander'))
Pandoc.brew(system.file('examples/minimal.brew', package='pander'),
  output = tempfile(), convert = 'html')
Pandoc.brew(system.file('examples/short-code-long-report.brew', package='pander'))
Pandoc.brew(system.file('examples/short-code-long-report.brew', package='pander'),
  output = tempfile(), convert = 'html')

## brew returning R objects
str(Pandoc.brew(text='Pi equals to <%=pi%>.
And here are some random data:\n<%=runif(10)%>'))

str(Pandoc.brew(text='# Header <%=1%>\nPi is <%=pi%> which is smaller then <%=2%>.
foo\nbar\n <%=3%>\n<%=mtcars[1:2,]%>'))

str(Pandoc.brew(text='<%for (i in 1:5) {%>
Pi has a lot (<%=i%>) of power: <%=pi^i%><%}%>'))

## End(Not run)

pander

An R 'Pandoc' Writer

v0.6.3

AGPL-3 | file LICENSE

Authors

Gergely Daróczi [aut, cre] (<https://orcid.org/0000-0003-3149-8537>), Roman Tsegelskyi [aut]

Initial release

2018-11-06