hugo/content/en/render-hooks/passthrough.md
Bjørn Erik Pedersen dec8cd4ada Squashed 'docs/' changes from fcc3ed651..a49697e53
a49697e53 Add private use subtag requirements to multilingual page
a5c6bb4da Add INFINI Pizza search engine
45b732efa Fix template lookup order for AMP pages
30c672d0b netlify: Hugo 0.133.1
7c766e724 Update page resources documentation
ca802fbec Document how to enable AsciiDoc syntax highlighting
c3350f4cf Update definition of falsy to include zero time.Time values
b0e5ab051 Fir typo
60f6cb63b Update migrations.md
ec52c7ba1 Improve formatting of example code
e5681ad01 Improve formatting of example code
bdf3ffc73 Clarify the various next/prev methods
b5505d22a Clarify template lookup order for shortcodes
cf8dd7034 Improve embedded.md
e5dee2651 Update transform.ToMath
4d419a128 Update pagination configuration to use new struct
05d4fd597 Update PrevInSection.md
fd33370ed Add new-in 0.133.0
f9062042f Add the new page config section
205645e97 Remove out-dated  new-in
3ed3673f7 Fix typo
41df91659 Document the 'else with' construct introduced with Go 1.23
9c4697ab3 netlify: Hugo 0.133.0
62506b052 Merge branch 'temp133'
877e1bfcd Add config options page.nextPrevSortOrder/nextPrevInSectionSortOrder
eb159fe62 Update menu.md
efa7795a0 Update theme
dbe8911ad netlify: Hugo 0.132.2
2f793d328 Document passthrough render hooks
a7ce9a5e8 netlify: Hugo 0.132.1
2c137cb48 Update blockquotes.md
e0fa2f0d1 Add new-in badge to blockquote render hook page
bf42bbe6b Update references to render hooks
85a3d9958 Update theme
2dae72128 Document blockquote render hooks
8f5afb55d Update plainify return type
160f22d0e netlify: Hugo 0.132.0
82b5586fb Document transform.ToMath
1efcbcddb tpl/transform: Make Plainify and ToMath return template.HTML
31727be2e docs: Regen docshelper
88a421426 Merge commit 'a6e635ca7d905d9ec3ffd708db2694f680b03aae'

git-subtree-dir: docs
git-subtree-split: a49697e536ee0d477ab4e552cfa8dc74debeff27
2024-09-01 14:51:15 +02:00

125 lines
4 KiB
Markdown
Executable file

---
title: Passthrough render hooks
linkTitle: Passthrough
description: Create a passthrough render hook to override the rendering of text snippets captured by the Goldmark passthrough extension.
categories: [render hooks]
keywords: []
menu:
docs:
parent: render-hooks
weight: 80
weight: 80
toc: true
---
{{< new-in 0.132.0 >}}
## Overview
Hugo uses [Goldmark] to render Markdown to HTML. Goldmark supports custom extensions to extend its core functionality. The Goldmark [passthrough extension] captures and preserves raw Markdown within delimited snippets of text, including the delimiters themselves. These are known as _passthrough elements_.
[Goldmark]: https://github.com/yuin/goldmark
[passthrough extension]: /getting-started/configuration-markup/#passthrough
Depending on your choice of delimiters, Hugo will classify a passthrough element as either _block_ or _inline_. Consider this contrived example:
{{< code file=content/sample.md >}}
This is a
\[block\]
passthrough element with opening and closing block delimiters.
This is an \(inline\) passthrough element with opening and closing inline delimiters.
{{< /code >}}
Update your site configuration to enable the passthrough extension and define opening and closing delimiters for each passthrough element type, either `block` or `inline`. For example:
{{< code-toggle file=hugo >}}
[markup.goldmark.extensions.passthrough]
enable = true
[markup.goldmark.extensions.passthrough.delimiters]
block = [['\[', '\]'], ['$$', '$$']]
inline = [['\(', '\)']]
{{< /code-toggle >}}
In the example above there are two sets of `block` delimiters. You may use either one in your Markdown.
The Goldmark passthrough extension is often used in conjunction with the MathJax or KaTeX display engine to render [mathematical expressions] written in [LaTeX] or [Tex].
[mathematical expressions]: /content-management/mathematics/
[LaTeX]: https://www.latex-project.org/
[Tex]: https://en.wikipedia.org/wiki/TeX
To enable custom rendering of passthrough elements, create a render hook.
## Context
Passthrough render hook templates receive the following [context]:
[context]: /getting-started/glossary/#context
###### Attributes
(`map`) The [Markdown attributes], available if you configure your site as follows:
[Markdown attributes]: /content-management/markdown-attributes/
{{< code-toggle file=hugo >}}
[markup.goldmark.parser.attribute]
block = true
{{< /code-toggle >}}
Hugo populates the `Attributes` map for _block_ passthrough elements. Markdown attributes are not applicable to _inline_ elements.
###### Inner
(`string`) The inner content of the passthrough element, excluding the delimiters.
###### Ordinal
(`int`) The zero-based ordinal of the passthrough element on the page.
###### Page
(`page`) A reference to the current page.
###### PageInner
(`page`) A reference to a page nested via the [`RenderShortcodes`] method. [See details](#pageinner-details).
[`RenderShortcodes`]: /methods/page/rendershortcodes
###### Position
(`string`) The position of the passthrough element within the page content.
###### Type
(`bool`) The passthrough element type, either `block` or `inline`.
## Example
As an alternative to rendering mathematical expressions with the MathJax or KaTeX display engine, create a passthrough render hook which calls the [`transform.ToMath`] function:
[`transform.ToMath`]: /functions/transform/tomath/
{{< code file=layouts/_default/_markup/render-passthrough.html copy=true >}}
{{ if eq .Type "block" }}
{{ $opts := dict "displayMode" true }}
{{ transform.ToMath .Inner $opts }}
{{ else }}
{{ transform.ToMath .Inner }}
{{ end }}
{{< /code >}}
Although you can use one template with conditional logic as shown above, you can also create separate templates for each [`Type`](#type) of passthrough element:
```text
layouts/
└── _default/
└── _markup/
├── render-passthrough-block.html
└── render-passthrough-inline.html
```
{{% include "/render-hooks/_common/pageinner.md" %}}