Working with Code environments in texor

This is a small sample article to demonstrate usage of texor to convert code environments.

1 Introduction

Pandoc naturally converts verbatim environment easily, however the redefination of other commands such as example, example*, Sinput etc to verbatim does not work well in pandoc.

Hence, the texor package uses a stream editor to search find and replace matching code environments to verbatim before pandoc touches it.

This way the the code is not lost in conversion, also a pandoc extension is used to add attributes to the markdown code using fenced_code_attributes

Code Environment types are well summarized in the table 1

Table 1: Code Environment support in texor

Code Environment Type
Example	example	example*
S.series	Sin	Sout	Sinput	Soutput	Scode
Special Verbatim	boxedverbatim

2 Environments

Verbatim Series

While verbatim is naturally supported in pandoc,other extensions of verbatim environment like boxedverbatim from moreverb package (Fairbairns, A.  Duggan, R.  Schöpf and V.  Eijkhout 2011) falls back to normal verbatim.

1. verbatim :

print("Hello world")

2. boxedverbatim :

print("Hello world")

S series

S series code environement is defined in Rjournal.sty file. Most of these are extensions of verbatim environment and retain the original formatting of the content in HTML.

1. Sinput :

print("Hello world")

2. Soutput :

[1] "hello world"

3. Sin :

print("Hello world")

4. Sout :

[1] "hello world"

Example series

Example series of code environment is defined in Rjournal.sty file. Examples are extensions of verbatim environment and retain the original formatting of the content in HTML.

1. example :

print("Hello world")

2. example* :

print("Hello world")

3 Code in Figure Environments

A small example of this is visble in 1. This is a common practice in Rnews articles as it used to add a boxed border around the code which looks attractive. However, in web articles there isn’t much advantage to it.

code_in_figure <- function() {
  if (pandoc_version >= 3) {
    print("Code in Figure Supported")
  }
  else {
    print("code in Figure not supported")
  }
}

Figure 1: Example Code inside Figure environment

Pandoc v3 or greater (Krewinkel and A.  Lucero 2023) has a Figure object which allows non-image figures to be treated like one. This is why texor package requires atleast version 3 of pandoc.

4 Code in Table Environments

We can use code environments in a table using minipage environments. This is not a common practice among LaTeX article authors, but a few articles had such complex structures. So, as a example to demonstrate pandoc and texor package’s capabilities, I have included a few of them.

Table 2 is an example of code environments within a table.

Table 2: Code in a table

Language	Function Defination Syntax
R	fun <- function(){ print("A function in R") return(0) }
Python	def fun(): print("A function in Python")
Lua	function fun() print("A function in Lua") end

A similar arrangement can be had for figures/plots besides code environment. Table 3 demonstrates a table with code and figure.

Table 3: Code and Plot side by side

Code	Plot
x <- 1:100 y <- dbinom(x,100,prob = 0.5) plot(x,y)	image

5 Inline Code usage

Using inline code in LaTeX is possible using \verb command. It would be repoduced similarly, as a Inline code element.

\verb|x <- 1:100|

will be represented as x <- 1:100 in Inline format.

6 Code chunks using Schunk

Code chunks within an Schunk environment to demonstrate Input/Output

Input :

print("Hello world")

Output :

[1] "hello world"

Similar arrangement can be had for Plots as well using figure environnment.

Input :

x <- 1:100
y <- dbinom(x,100,prob = 0.5)
plot(x,y)

Output :

7 Including ‘R code chunks’

Including R code chunks in an article that is to be converted to R markdown can be a bit tricky as the knitr package will interpret and execute the R code chunks as actual code bits. A workaround for this issue has been described in this posit support article. Below is an example with the workaround adapted from (Nathan Stephens 2022).

```{r}
plot(cars)
```

8 Summary

In summary the texor package supports:

• Almost all code environments in RJournal.

• Code Highlight for R language.

• Inline Code.

• Code in different environments like tables/figures.

9 CRAN packages used

texor, knitr

10 CRAN Task Views implied by cited packages

ReproducibleResearch

11 Note

This article is converted from a Legacy LaTeX article using the texor package. The pdf version is the official version. To report a problem with the html, refer to CONTRIBUTE on the R Journal homepage.