Integrating objects with IRKernel

Question

Similar to how you can write _repr_html_ for a repr on an object in Python, I'd like to be able to decorate objects in R for inspection with the IRKernel (while not interfering with regular R usage of the library). How should I be writing R to make it nicer for Jupyter users?

Answer 1

The main kind of classes in R are S3 classes, and these are what IRKernel's repr library knows about.

Methods on S3 classes are more like generic functions. repr declares a number of generic functions like repr_html. If you define a class called frob, you can provide a function called repr_html.frob which returns the HTML to represent your object. All the magic for method lookup is based on the name, as far as I know, so you can define the repr_html.frob function as normal - it doesn't matter what package it's in, so long as the user loads the package before the kernel tries to display your object.

The generic functions repr declares are:

• repr_text
• repr_html
• repr_markdown
• repr_latex
• repr_json
• repr_javascript
• repr_pdf
• repr_png
• repr_jpg
• repr_svg

As in Python, you can define as many or as few of these as makes sense. See the repr code for some examples.