hugo/docs/content/en/content-management/syntax-highlighting.md
Bjørn Erik Pedersen 5fd1e74903
Merge commit '9b0050e9aabe4be65c78ccf292a348f309d50ccd' as 'docs'
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git subtree add --prefix=docs/ https://github.com/gohugoio/hugoDocs.git master --squash
```

Closes #11925
2024-01-27 10:48:57 +01:00

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---
title: Syntax highlighting
description: Hugo comes with really fast syntax highlighting from Chroma.
categories: [content management]
keywords: [highlighting,chroma,code blocks,syntax]
menu:
docs:
parent: content-management
weight: 240
weight: 240
toc: true
aliases: [/extras/highlighting/,/extras/highlight/,/tools/syntax-highlighting/]
---
Hugo uses [Chroma](https://github.com/alecthomas/chroma) as its code highlighter; it is built in Go and is really, really fast.
## Configure syntax highlighter
See [Configure Highlight](/getting-started/configuration-markup#highlight).
## Generate syntax highlighter CSS
If you run with `markup.highlight.noClasses=false` in your site configuration, you need a style sheet.
You can generate one with Hugo:
```sh
hugo gen chromastyles --style=monokai > syntax.css
```
Run `hugo gen chromastyles -h` for more options. See https://xyproto.github.io/splash/docs/ for a gallery of available styles.
## Highlight shortcode
Highlighting is carried out via the built-in [`highlight` shortcode](/content-management/shortcodes/#highlight). It takes exactly one required parameter for the programming language to be highlighted and requires a closing shortcode.
Options:
* `linenos`: configure line numbers. Valid values are `true`, `false`, `table`, or `inline`. `false` will turn off line numbers if it's configured to be on in site configuration. `table` will give copy-and-paste friendly code blocks.
* `hl_lines`: lists a set of line numbers or line number ranges to be highlighted.
* `linenostart=199`: starts the line number count from 199.
* `anchorlinenos`: Configure anchors on line numbers. Valid values are `true` or `false`;
* `lineanchors`: Configure a prefix for the anchors on line numbers. Will be suffixed with `-`, so linking to the line number 1 with the option `lineanchors=prefix` adds the anchor `prefix-1` to the page.
* `hl_inline` Highlight inside a `<code>` (inline HTML element) tag. Valid values are `true` or `false`. The `code` tag will get a class with name `code-inline`. {{< new-in 0.101.0 >}}
### Example: highlight shortcode
```go-html-template
{{</* highlight go "linenos=table,hl_lines=8 15-17,linenostart=199" */>}}
// ... code
{{</* / highlight */>}}
```
Gives this:
{{< highlight go "linenos=table,hl_lines=8 15-17,linenostart=199" >}}
// GetTitleFunc returns a func that can be used to transform a string to
// title case.
//
// The supported styles are
//
// - "Go" (strings.Title)
// - "AP" (see https://www.apstylebook.com/)
// - "Chicago" (see https://www.chicagomanualofstyle.org/home.html)
//
// If an unknown or empty style is provided, AP style is what you get.
func GetTitleFunc(style string) func(s string) string {
switch strings.ToLower(style) {
case "go":
return strings.Title
case "chicago":
return transform.NewTitleConverter(transform.ChicagoStyle)
default:
return transform.NewTitleConverter(transform.APStyle)
}
}
{{< / highlight >}}
## Highlight Hugo/Go template code
For highlighting Hugo/Go template code on your page, add `/*` after the opening double curly braces and `*/` before closing curly braces.
``` go
{{</*/* myshortcode */*/>}}
```
Gives this:
``` go
{{</* myshortcode */>}}
```
## Highlight template function
See [Highlight](/functions/transform/highlight/).
## Highlighting in code fences
Highlighting in code fences is enabled by default.
````txt
```go {linenos=table,hl_lines=[8,"15-17"],linenostart=199}
// ... code
```
````
Gives this:
```go {linenos=table,hl_lines=[8,"15-17"],linenostart=199}
// GetTitleFunc returns a func that can be used to transform a string to
// title case.
//
// The supported styles are
//
// - "Go" (strings.Title)
// - "AP" (see https://www.apstylebook.com/)
// - "Chicago" (see https://www.chicagomanualofstyle.org/home.html)
//
// If an unknown or empty style is provided, AP style is what you get.
func GetTitleFunc(style string) func(s string) string {
switch strings.ToLower(style) {
case "go":
return strings.Title
case "chicago":
return transform.NewTitleConverter(transform.ChicagoStyle)
default:
return transform.NewTitleConverter(transform.APStyle)
}
}
```
The options are the same as in the [highlighting shortcode](/content-management/syntax-highlighting/#highlight-shortcode), including `linenos=false`, but note the slightly different Markdown attribute syntax.
## List of Chroma highlighting languages
The full list of Chroma lexers and their aliases (which is the identifier used in the `highlight` template func or when doing highlighting in code fences):
{{< chroma-lexers >}}