Question

I am trying to write a Jekyll converter for R Markdown files. I created RMarkdownConverter.rb and placed it in my _plugins directory. I have verified that other plugins are working but this one is not. I also don’t see any error messages, including the ones I put in myself. It seems this is not being used. However, Jekyll is generating an HTML file for my .Rmd file but simply processes the R chuck as code chuck. Any help or thoughts would be greatly appreciated.

RMarkdownConverter.rb file:

module Jekyll
    class RMarkdownConverter < Converter
        safe true
        priority :low

    def setup
      STDERR.puts "Setting up R Markdown..."
      return if @setup
      require 'rinruby'
      @setup = true
    rescue
      STDERR.puts 'do `gem install rinruby`'
      raise FatalException.new("Missing dependency: rinruby")
    end

        def matches(ext)
            ext =~ /Rmd/i
        end

        def output_ext(ext)
           '.html'
        end

        def convert(content)
      setup
      STDERR.puts "Using R Markdown..."
      R.eval "require(knitr)"
      R.eval "render_markdown(strict=TRUE)"
      R.assign "content", content
      STDERR.puts content
      R.eval "out <- knit(text=content)"
      R.eval "print(out)"
        end
    end
end

The contents of my first R Markdown post:

--- 
layout: post
title: Using (R) Markdown, Jekyll, and Github for Blogging
published: true
tags: R R-Bloggers Jekyll github
type: post
status: publish
---

First, we need to install [RinRuby](https://sites.google.com/a/ddahl.org/rinruby-users/) to call R from Ruby. In the terminal, execute:

    gem install rinruby

First R chuck:

```{r}
2 + 2
```

Answer 1

Try replacing the last few lines with the following

R.assign "content", content
R.eval "knitr::render_markdown(strict = TRUE)"
R.pull "(knitr::knit2html(text = content, fragment.only = TRUE))"

I think you need R.pull to copy the contents of R output to Ruby. Moreover, I would recommend directly converting from Rmd to html. I have used this strategy successfully in working with Ruhoh which is another ruby based blogging platform.

UPDATE. It is very odd but using the extension rmd seems to conflict with md. I changed it randomly to ram and jekyll seems to pick it up correctly. I am not sure why.