hugo/docs/content/en/functions/highlight.md
2023-07-29 11:17:28 +02:00

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---
title: highlight
description: Renders code with a syntax highlighter.
categories: [functions]
menu:
docs:
parent: functions
keywords: [highlighting,code blocks,syntax]
signature: ["transform.Highlight INPUT LANG [OPTIONS]","highlight INPUT LANG [OPTIONS]"]
relatedfuncs: []
toc: true
---
The `highlight` function uses the [Chroma] syntax highlighter, supporting over 200 languages with more than 40 available styles.
## Parameters
INPUT
: The code to highlight.
LANG
: The language of the code to highlight. Choose from one of the [supported languages]. Case-insensitive.
OPTIONS
: An optional, comma-separated list of zero or more [options]. Set default values in [site configuration].
## Options
lineNos
: Boolean. Default is `false`.\
Display a number at the beginning of each line.
lineNumbersInTable
: Boolean. Default is `true`.\
Render the highlighted code in an HTML table with two cells. The left table cell contains the line numbers. The right table cell contains the code, allowing a user to select and copy the code without line numbers. Irrelevant if `lineNos` is `false`.
anchorLineNos
: Boolean. Default is `false`.\
Render each line number as an HTML anchor element, and set the `id` attribute of the surrounding `<span>` to the line number. Irrelevant if `lineNos` is `false`.
lineAnchors
: String. Default is `""`.\
When rendering a line number as an HTML anchor element, prepend this value to the `id` attribute of the surrounding `<span>`. This provides unique `id` attributes when a page contains two or more code blocks. Irrelevant if `lineNos` or `anchorLineNos` is `false`.
lineNoStart
: Integer. Default is `1`.\
The number to display at the beginning of the first line. Irrelevant if `lineNos` is `false`.
hl_Lines
: String. Default is `""`.\
A space-separated list of lines to emphasize within the highlighted code. To emphasize lines 2, 3, 4, and 7, set this value to `2-4 7`. This option is independent of the `lineNoStart` option.
hl_inline
: Boolean. Default is `false`.\
Render the highlighted code without a wrapping container.
style
: String. Default is `monokai`.\
The CSS styles to apply to the highlighted code. See the [style gallery] for examples. Case-sensitive.
noClasses
: Boolean. Default is `true`.\
Use inline CSS styles instead of an external CSS file. To use an external CSS file, set this value to `false` and [generate the file with the hugo client][hugo client].
tabWidth
: Integer. Default is `4`.\
Substitute this number of spaces for each tab character in your highlighted code. Irrelevant if `noClasses` is `false`.
guessSyntax
: Boolean. Default is `false`.\
If the `LANG` parameter is blank or an unrecognized language, auto-detect the language if possible, otherwise use a fallback language.
{{% note %}}
Instead of specifying both `lineNos` and `lineNumbersInTable`, you can use the following shorthand notation:
`lineNos=inline`
: equivalent to `lineNos=true` and `lineNumbersInTable=false`
`lineNos=table`
: equivalent to `lineNos=true` and `lineNumbersInTable=true`
{{% /note %}}
## Examples
```go-html-template
{{ $input := `fmt.Println("Hello World!")` }}
{{ transform.Highlight $input "go" }}
{{ $input := `console.log('Hello World!');` }}
{{ $lang := "js" }}
{{ transform.Highlight $input $lang "lineNos=table, style=api" }}
{{ $input := `echo "Hello World!"` }}
{{ $lang := "bash" }}
{{ $options := dict "lineNos" "table" "style" "dracula" }}
{{ transform.Highlight $input $lang $options }}
```
[Chroma]: https://github.com/alecthomas/chroma
[hugo client]: /commands/hugo_gen_chromastyles
[options]: #options
[site configuration]: /getting-started/configuration-markup#highlight
[style gallery]: https://xyproto.github.io/splash/docs/
[supported languages]: /content-management/syntax-highlighting#list-of-chroma-highlighting-languages