Code blocks

Code blocks and examples are an essential part of technical project documentation. Material for MkDocs provides different ways to set up syntax highlighting for code blocks, either during build time using Pygments or during runtime using a JavaScript syntax highlighter.

Configuration

This configuration enables syntax highlighting on code blocks and inline code blocks, and allows to include source code directly from other files. Add the following lines to mkdocs.yml:

markdown_extensions:
  - pymdownx.highlight:
      anchor_linenums: true
      line_spans: __span
      pygments_lang_class: true
  - pymdownx.inlinehilite
  - pymdownx.snippets
  - pymdownx.superfences

The following sections discuss how to use different syntax highlighting features with Pygments, the recommended highlighter, so they don't apply when using a JavaScript syntax highlighter.

See additional configuration options:

• Highlight
• InlineHilite
• SuperFences
• Snippets

Code copy button

Code blocks can automatically render a button on the right side to allow the user to copy a code block's contents to the clipboard. Add the following to mkdocs.yml to enable them globally:

theme:
  features:
    - content.code.copy

??? info "Enabling or disabling code copy buttons for a specific code block"

If you don't want to enable code copy buttons globally, you can enable them
for a specific code block by using a slightly different syntax based on the
[Attribute Lists] extension:

```` yaml
``` { .yaml .copy }
# Code block content
```
````

Note that the language shortcode which has to come first must now also be
prefixed by a `.`. Similarly, the copy button can also be disabled for a
specific code block:

```` { .yaml .no-copy }
``` { .yaml .no-copy }
# Code block content
```
````

Code selection button

Code blocks can include a button to allow for the selection of line ranges by the user, which is perfect for linking to a specific subsection of a code block. This allows the user to apply line highlighting dynamically. Add the following to mkdocs.yml to enable it globally:

theme:
  features:
    - content.code.select

??? info "Enabling or disabling code selection buttons for a specific code block"

If you don't want to enable code selection buttons globally, you can enable
them for a specific code block by using a slightly different syntax based on
the [Attribute Lists] extension:

```` yaml
``` { .yaml .select }
# Code block content
```
````

Note that the language shortcode which has to come first must now also be
prefixed by a `.`. Similarly, the selection button can also be disabled for
a specific code block:

```` { .yaml .no-select }
``` { .yaml .no-select }
# Code block content
```
````

Code annotations

Code annotations offer a comfortable and friendly way to attach arbitrary content to specific sections of code blocks by adding numeric markers in block and inline comments in the language of the code block. Add the following to mkdocs.yml to enable them globally:

theme:
  features:
    - content.code.annotate # (1)!

1. :man_raising_hand: I'm a code annotation! I can contain code, formatted text, images, ... basically anything that can be written in Markdown.

??? info "Enabling code annotations for a specific code block"

If you don't want to enable code annotations globally, because you don't
like the automatic inlining behavior, you can enable them for a specific
code block by using a slightly different syntax based on the
[Attribute Lists] extension:

```` yaml
``` { .yaml .annotate }
# Code block content
```
````

Note that the language shortcode which has to come first must now also be
prefixed by a `.`.

Custom selectors

Normally, code annotations can only be placed in comments, as comments can be considered safe for placement. However, sometimes it might be necessary to place annotations in parts of the code block where comments are not allowed, e.g. in strings.

Additional selectors can be set per-language:

extra:
  annotate:
    json: [.s2] # (1)!

1. .s2 is the name of the lexeme that Pygments generates for double-quoted strings. If you want to use a code annotation in another lexeme than a comment, inspect the code block and determine which lexeme needs to be added to the list of additional selectors.

   Important: Code annotations cannot be split between lexemes.

Now, code annotations can be used from within strings in JSON:

{
  "key": "value (1)"
}

1. :man_raising_hand: I'm a code annotation! I can contain code, formatted text, images, ... basically anything that can be written in Markdown.

Usage

Code blocks must be enclosed with two separate lines containing three backticks. To add syntax highlighting to those blocks, add the language shortcode directly after the opening block. See the list of available lexers to find the shortcode for a given language:

``` py
import tensorflow as tf
```

import tensorflow as tf

Adding a title

In order to provide additional context, a custom title can be added to a code block by using the title="<custom title>" option directly after the shortcode, e.g. to display the name of a file:

``` py title="bubble_sort.py"
def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]
```

def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]

Adding annotations

Code annotations can be placed anywhere in a code block where a comment for the language of the block can be placed, e.g. for JavaScript in // ... and /* ... */, for YAML in # ..., etc.[^1]:

[^1]: Code annotations require syntax highlighting with Pygments – they're currently not compatible with JavaScript syntax highlighters, or languages that do not have comments in their grammar. However, we're actively working on supporting alternate ways of defining code annotations, allowing to always place code annotations at the end of lines.

``` yaml
theme:
  features:
    - content.code.annotate # (1)
```

1.  :man_raising_hand: I'm a code annotation! I can contain `code`, __formatted
    text__, images, ... basically anything that can be written in Markdown.

theme:
  features:
    - content.code.annotate # (1)

Stripping comments

If you wish to strip the comment characters surrounding a code annotation, simply add an ! after the closing parenthesis of the code annotation:

``` yaml
# (1)!
```

1.  Look ma, less line noise!

# (1)!

Note that this only allows for a single code annotation to be rendered per comment. If you want to add multiple code annotations, comments cannot be stripped for technical reasons.

Adding line numbers

Line numbers can be added to a code block by using the linenums="<start>" option directly after the shortcode, whereas <start> represents the starting line number. A code block can start from a line number other than 1, which allows to split large code blocks for readability:

``` py linenums="1"
def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]
```

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def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]

Highlighting specific lines

Specific lines can be highlighted by passing the line numbers to the hl_lines argument placed right after the language shortcode. Note that line counts start at 1, regardless of the starting line number specified as part of linenums:

=== "Lines"

```` markdown title="Code block with highlighted lines"
``` py hl_lines="2 3"
def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]
```
````

<div class="result" markdown>

``` py linenums="1" hl_lines="2 3"
def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]
```

</div>

=== "Line ranges"

```` markdown title="Code block with highlighted line range"
``` py hl_lines="3-5"
def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]
```
````

<div class="result" markdown>

``` py linenums="1" hl_lines="3-5"
def bubble_sort(items):
    for i in range(len(items)):
        for j in range(len(items) - 1 - i):
            if items[j] > items[j + 1]:
                items[j], items[j + 1] = items[j + 1], items[j]
```

</div>

Highlighting inline code blocks

When InlineHilite is enabled, syntax highlighting can be applied to inline code blocks by prefixing them with a shebang, i.e. #!, directly followed by the corresponding language shortcode.

The `#!python range()` function is used to generate a sequence of numbers.

Embedding external files

When Snippets is enabled, content from other files (including source files) can be embedded by using the --8<-- notation directly from within a code block:

``` title=".browserslistrc"
--8<-- ".browserslistrc"
```

last 4 years

Customization

Custom syntax theme

If Pygments is used, Material for MkDocs provides the styles for code blocks, which are built with a custom and well-balanced palette that works equally well for both color schemes:

• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-number-color) " } --md-code-hl-number-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-special-color) " } --md-code-hl-special-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-function-color) " } --md-code-hl-function-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-constant-color) " } --md-code-hl-constant-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-keyword-color) " } --md-code-hl-keyword-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-string-color) " } --md-code-hl-string-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-name-color) " } --md-code-hl-name-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-operator-color) " } --md-code-hl-operator-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-punctuation-color) " } --md-code-hl-punctuation-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-comment-color) " } --md-code-hl-comment-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-generic-color) " } --md-code-hl-generic-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-variable-color) " } --md-code-hl-variable-color

Code block foreground, background and line highlight colors are defined via:

• :material-checkbox-blank-circle:{ style="color: var(--md-code-fg-color) " } --md-code-fg-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-bg-color) " } --md-code-bg-color
• :material-checkbox-blank-circle:{ style="color: var(--md-code-hl-color) " } --md-code-hl-color

Let's say you want to change the color of "strings". While there are several types of string tokens, they use the same color. You can assign a new color by using an additional style sheet:

=== ":octicons-file-code-16: docs/stylesheets/extra.css"

``` css
:root > * {
  --md-code-hl-string-color: #0FF1CE;
}
```

=== ":octicons-file-code-16: mkdocs.yml"

``` yaml
extra_css:
  - stylesheets/extra.css
```

If you want to tweak a specific type of string, e.g. `backticks`, you can lookup the specific CSS class name in the syntax theme definition, and override it as part of your additional style sheet:

=== ":octicons-file-code-16: docs/stylesheets/extra.css"

``` css
.highlight .sb {
  color: #0FF1CE;
}
```

=== ":octicons-file-code-16: mkdocs.yml"

``` yaml
extra_css:
  - stylesheets/extra.css
```

Annotation tooltip width

If you have a lot of content hosted inside your code annotations, it can be a good idea to increase the width of the tooltip by adding the following as part of an additional style sheet:

=== ":octicons-file-code-16: docs/stylesheets/extra.css"

``` css
:root {
  --md-tooltip-width: 600px;
}
```

=== ":octicons-file-code-16: mkdocs.yml"

``` yaml
extra_css:
  - stylesheets/extra.css
```

This will render annotations with a larger width:

# (1)!