1 Introduction

Markdown is a simple markup language. The primary output document type is HTML, but use of pandoc¹ means that one source markdown file can be processed into many different output document formats including HTML, Microsoft Word, pdf (via LATEX), Open Office, rich text format, and a variety of slide show presentation formats.

A variant of markdown has been developed for the R Statistical Software application (R Core Team, 2015). This has been achieved through development of a number of add-on packages, principally the knitr package (Xie, 2015), the rmarkdown package (Allaire et al., 2015), and their dependencies. R has proven to offer more to a blind user than any other statistical software in common use today (Godfrey and Loots, 2014). Combining the power of R with the ease of document preparation offered by markdown gives new workflow options to all R users. Blind people can benefit because we get the accessibility features we need with no extra effort as authors.

The single drawback to the use of markdown and R in combination is the inaccessibility of the primary integrated development environment (IDE) for R called RStudio² (Godfrey, 2013). RStudio is a wonderful tool for sighted users, but there is very little chance that any effort will go into making it accessible. In most situations, the blind user is not missing much by not having RStudio available; the current exception is the absence of the ability to turn a markdown document with embedded statistical analyses into a beautiful final document. In response to this, we have developed a small text editor application in Python called WriteR, that meets this need for blind users. See Figure 1 for a screen shot of a document being edited in the WriteR application.

To prove the usefulness of the workflow discussed in this paper, the oral presentation accompanying this work has been developed using R markdown and the WriteR text editor; the presentation will also include a practical demonstration.

2 Presentation of Statistical Content

An R markdown document in its most simple form is just a markdown document with only two additional constructs. R content is added as part of a sentence, or as standalone blocks of R code input and associated output. A block of code looks like:

The first and last three characters are called ‘backticks’ in many documentation resources, but are known as accent grave symbols by screen readers such as JAWS (Freedom Scientific, 2015) and NVDA (NVDA Team, 2015). The other elements of the first line tell how the code block should be processed. The above example uses R to process the commands using default settings. ‘Example1’ is a reference for this block; other options exist for controlling the presentation of the input and output. This block has only one line of R code which is just a comment.

In comparison, the R markdown block:

has a request to suppress printing of the R commands. The result of this calculation would be printed out in the output document as it would appear in an R session window. More usefully however, the user can insert R commands in the prose of an article using a slightly different construct. To include the numeric representation for this mean in a sentence, the user would enter ‘r mean(x)‘ in the sentence.

Using these two constructs it is very easy to produce a document that can be updated on demand. Common scenarios that highlight the need to do this include tasks where data is updated over time leading to reports that depend on this data. In an educational setting, the opportunity for students to review their work and insert any additional tasks so that an analysis can be improved saves time and energy. This advantage is even more noticeable for blind students who often take longer to edit and perfect documents than do their sighted peers.

3 A sample assignment solution

To illustrate how easy it is to create the solution for an assignment question, we process the R markdown document given in Figure 2 and present it as the screen shot of the HTML file being viewed in a browser (given in Figure 3).

The processing of this R markdown file into HTML used an intermediate markdown file (shown in Figure 4) which has included the statistical content from the execution of the R commands.

4 Accessibility of Markdown and WriteR

We have ensured that the WriteR interface is accessible for screen reader users. Testing has been undertaken using JAWS and NVDA screen readers. We have made use of hot keys for commonly used tasks and all menu items and dialogue boxes are accessible to blind users. All input for the R markdown documents can be entered using 8-dot computer braille with ease; users of 6-dot braille codes will have to overcome the challenges of typing various forms of brackets (parentheses, square brackets and curly braces) as well as a few symbols necessary for creating formatted content in their markdown documents. Standard (QWERTY) keyboards provide a completely accessible means of authoring all markdown documents.

The HTML documents that are created by processing R markdown documents are very accessible. Markdown incorporates use of heading levels and other simple formatting such as tables and bulleted or enumerated lists.

Mathematical content can be incorporated using MathML or MathJax, but there are reasons why these tools should be avoided. The most noticeable reason for wanting to avoid these means of presenting mathematical content is the need to add the relevant scripts into the header of all HTML documents which expands the size of the created HTML files. A smaller HTML file can be created that uses the same style of presentation as found on many webpages including http://www.wikipedia.com where mathematical content is produced using a graphic that has an alt tag containing the raw LATEX that created it. No matter which mode of presenting mathematical content is chosen, the user is constrained to a set of LATEX commands and environments and cannot develop their own LATEX commands.

5 Interface with R

The WriteR application is bundled with the BrailleR add-on package (Godfrey, 2015) for the R Statistical Software application (R Core Team, 2015).

Several functions for helping users get started with setting up WriteR and to start editing a document from their current R session have been incorporated into the BrailleR package. These functions include establishing default settings linking WriteR to the current version of R, incorporating the user’s name as the author of the R markdown document being edited, and offering suggested settings to build multiple output versions of the document as part of the document preparation process.

6 Conclusion

The use of the WriteR text editor as a means of creating R markdown documents has proven itself in a classroom setting during 2015. The first author has been able to type R markdown in front of a class and process the document into HTML for showing to students. Being able to demonstrate the use of R markdown and therefore show examples of how R can be used to achieve laboratory exercises in real time as against using pre-prepared documents creates a sense of authenticity that is important in the classroom setting.

Web resources noted in the text

¹See the pandoc home page at http://johnmacfarlane.net/pandoc/

²See http://rstudio.com

References