This passes the custom codeblock element defined here on the markdown here

Custom behavior for classes.

Different document. The example file here applies highlight.js classes to elements, and then looks at the codeblock class for custom actions.

R code may be destined for R Markdown, so we’ll make all R code copy to R markdown blocks.

    
r_code %>%
   is_made %>%
   of_pipes %>%
   that_can %>%
   wrap_around %>%
   and_you_just_paste_them_in

  

Indentation is important to python, so every python block gets buttons to change the indenting.

    
python = "a language_where"
  "indentation really matters"
  "for copying."

  

Javascript code can be executed straight in the browser: I can’t think of any reason not to do that!

    alert('Usage of eval is a bad idea!');