Is it possible to install pandoc on windows using an R command?

Question

I would like to download and install pandoc on a windows 7 machine, by running a command in R. Is that possible?

(I know I can do this manually, but when I'd show this to students - the more steps I can organize within an R code chunk - the better)

Answer 1

What about simply downloading the most recent version of the installer and starting that from R:

1. a) Identify the most recent version of Pandoc and grab the URL with the help of the XML package:

   library(XML)
   page     <- readLines('http://code.google.com/p/pandoc/downloads/list', warn = FALSE)
   pagetree <- htmlTreeParse(page, error=function(...){}, useInternalNodes = TRUE, encoding='UTF-8')
   url      <- xpathSApply(pagetree, '//tr[2]//td[1]//a ', xmlAttrs)[1]
   url      <- paste('http', url, sep = ':')
   

   b) Or apply some regexp magic thanks to @G.Grothendieck instead (no need for the XML package this way):

   page <- readLines('http://code.google.com/p/pandoc/downloads/list', warn = FALSE)
   pat  <- "//pandoc.googlecode.com/files/pandoc-[0-9.]+-setup.exe"
   line <- grep(pat, page, value = TRUE); m <- regexpr(pat, line)
   url  <- paste('http', regmatches(line, m), sep = ':')
   

   c) Or simply check the most recent version manually if you'd feel like that:

   url <- 'http://pandoc.googlecode.com/files/pandoc-1.10.1-setup.exe'
   

2. Download the file as binary:

   t <- tempfile(fileext = '.exe')
   download.file(url, t, mode = 'wb')
   

3. And simply run it from R:

   system(t)
   

4. Remove the needless file after installation:

   unlink(t)
   

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PS: sorry, only tested on Windows XP