Understanding Rmarkdown and its Rendering Process

Rmarkdown is a markup language that combines the syntax of Markdown with the features of LaTeX. It’s widely used in academic publishing, data science, and technical writing. When rendered, Rmarkdown documents can produce high-quality HTML, PDF, and other formats. However, understanding how Rmarkdown renders content between sub-item bullets can be tricky.

In this article, we’ll delve into the world of Rmarkdown and explore why adding text between sub-item bullets sometimes results in a code block instead of the desired formatting.

The Role of YAML Front Matter

Rmarkdown documents typically start with YAML front matter. This section provides metadata about the document, such as its title, author, date, and other information. In our example, the YAML front matter is enclosed within triple backticks (````). Here’s what it looks like:

---
title: "My HTML page"
---

The YAML front matter plays a crucial role in determining how Rmarkdown renders the document.

The Rendering Process

When an Rmarkdown document is rendered, several steps occur. Here’s a simplified overview of the process:

1. Parsing: The renderer (e.g., rmarkdown::render in R) parses the Markdown and YAML sections to extract information about the document structure.
2. Building the Document Tree: Based on the parsed metadata, the renderer creates a hierarchical tree representing the document’s structure.
3. Rendering: The renderer then traverses this tree, applying formatting rules to each section.

Let’s take a closer look at what happens when rendering sub-item bullets:

• When the renderer encounters a bullet point (-, +, or -), it adds an item to the document tree with a certain level of nesting.
• If there is no content directly after the bullet point, the renderer simply moves on to the next line.

However, if there is content between the sub-item bullets, the renderer encounters two issues:

1. Incorrect Line Breaking: When the renderer encounters a bullet point followed by content, it assumes that this content should be part of the item and continues rendering until the next newline character (or a specific separator).
2. Code Block Indentation: If there are multiple lines after the initial line of content before another bullet point is encountered, the renderer may incorrectly assume that these lines are part of a code block.

Resolving the Issue: Adding Line Breaks

To resolve this issue and ensure that the text between sub-item bullets appears correctly, you can use one or both of the following techniques:

• Add line breaks: Use newline characters (\n) to separate your content from subsequent bullet points. This tells the renderer to render each line as a new item instead of grouping them together.
• Use triple backticks for block-level content: If you need to render large blocks of text or code, use triple backticks (````) to indicate that this is a block-level element.

Here’s an updated version of your original YAML front matter with these changes:

---
title: "My HTML page"
---

- Bullet 1

    + Sub-item 1  
    My content here ( new line )  

    + Sub-item 2  
    My content here  

Alternatively, you can use triple backticks to wrap your block-level content:

---
title: "My HTML page"
---

- Bullet 1

    + Sub-item 1  
    ``` 
    My content here
    ```
    
    + Sub-item 2  
    My content here  

Conclusion

In this article, we explored how Rmarkdown renders content between sub-item bullets and why sometimes results in a code block instead of the desired formatting. By understanding the rendering process and adding line breaks or using triple backticks to separate your content from subsequent bullet points, you can ensure that your text appears correctly.

However, keep in mind that there are many other factors that affect how Rmarkdown renders your document. Practice working with different formats, metadata, and custom CSS files to fine-tune your workflow and develop the skills needed for creating high-quality technical writing.

Last modified on 2023-07-01