highlight {downlit}

Highlight and link a code block

Description

This function:

• syntax highlights code

• links function calls to their documentation (where possible)

• in comments, translates ANSI escapes in to HTML equivalents.

Usage

highlight(text, classes = classes_chroma(), pre_class = NULL, code = FALSE)

classes_pandoc()

classes_chroma()

Arguments

text

String of code to highlight and link.

classes

A mapping between token names and CSS class names. Bundled classes_pandoc() and classes_chroma() provide mappings that (roughly) match Pandoc and chroma (used by hugo) classes so you can use existing themes.

pre_class

Class(es) to give output ⁠<pre>⁠.

code

If TRUE, wrap output in a ⁠<code>⁠ block

Value

If text is valid R code, an HTML ⁠<pre>⁠ tag. Otherwise, NA.

A string containing syntax highlighted HTML or NA (if text isn't parseable).

Options

downlit provides a number of options to control the details of the linking. They are particularly important if you want to generate "local" links.

• downlit.package: name of the current package. Determines when topic_index and article_index

• downlit.topic_index and downlit.article_index: named character vector that maps from topic/article name to path.

• downlit.rdname: name of current Rd file being documented (if any); used to avoid self-links.

• downlit.attached: character vector of currently attached R packages.

• downlit.local_packages: named character vector providing relative paths (value) to packages (name) that can be reached with relative links from the target HTML document.

• downlit.topic_path and downlit.article_path: paths to reference topics and articles/vignettes relative to the "current" file.

Examples

cat(highlight("1 + 1"))
cat(highlight("base::t(1:3)"))

# Unparseable R code returns NA
cat(highlight("base::t("))