| name | latte-templates |
| description | Invoke before creating or modifying .latte files, even for single-line changes. Provides Latte syntax, tags, filters, n:attributes, layouts, template inheritance, AJAX snippets, extensions, and Nette integration. Also trigger when user mentions Latte by name. |
Latte Templating System
Latte is a secure templating engine with context-aware escaping, intuitive syntax, and powerful template inheritance.
composer require latte/latte
Basic Syntax
{* this is a comment *}
<ul n:if="$items"> {* n:attribute *}
{foreach $items as $item} {* tag *}
<li>{$item|capitalize}</li> {* variable with filter *}
{/foreach}
</ul>
Printing Variables
{$name} {* prints escaped variable *}
{$user->name} {* object property *}
{$items[0]} {* array access *}
{='hello'|upper} {* expression with filter *}
{$html|noescape} {* disable escaping (use carefully!) *}
Latte uses context-aware escaping — output adapts to where the variable is printed. In <script> context, arrays and objects are automatically serialized to JSON:
{* Arrays auto-serialize to JSON inside <script> *}
<script type="application/ld+json">{$schemaData}</script>
<script>
let config = {$config};
</script>
Never use json_encode() in PHP + |noescape for this — Latte handles serialization and escaping safely on its own.
Filters
Filters modify output, written after |:
{$title|upper} {* HELLO *}
{$text|truncate:100} {* shortens to 100 chars *}
{$price|number:2} {* formats number *}
{$date|date:'j. n. Y'} {* formats date *}
{$name|lower|capitalize} {* chained filters *}
Common filters: upper, lower, capitalize, truncate, number, date, noescape, escapeUrl, stripHtml, trim, replace, first, last, length, sort, reverse
The filter | applies to the entire expression before it. Parentheses around PHP operators (like ??) before a filter are unnecessary:
{$a ?? $b|texyLine|noescape} {* correct – filter applies to result of ?? *}
{($a ?? $b)|texyLine|noescape} {* redundant – parentheses change nothing *}
See the complete filter reference for all available filters.
n:attributes
Pair tags can be written as HTML attributes:
{* These are equivalent: *}
{if $condition}<div>...</div>{/if}
<div n:if="$condition">...</div>
{* Applies to element content only: *}
<div n:inner-foreach="$items as $item">...</div>
{* Applies to tag only (not content): *}
<a href={$url} n:tag-if="$url">Link</a>
Conditions
{if $stock > 0}
In stock
{elseif $onWay}
On the way
{else}
Not available
{/if}
{ifset $user}...{/ifset} {* if variable exists *}
{* switch/case *}
{switch $type}
{case admin}Administrator
{case user}User
{default}Guest
{/switch}
Loops
{foreach $items as $item}
{$item->name}
{/foreach}
{foreach $items as $key => $item}
{$key}: {$item}
{/foreach}
{* With else for empty arrays *}
{foreach $items as $item}
<li>{$item}</li>
{else}
<li>No items found</li>
{/foreach}
{* Iterator variable *}
{foreach $items as $item}
{$iterator->counter}. {$item} {* 1, 2, 3... *}
{if $iterator->first}First!{/if}
{if $iterator->last}Last!{/if}
{/foreach}
{* Helper tags *}
{foreach $items as $item}
{first}<ul>{/first}
<li>{$item}</li>
{last}</ul>{/last}
{sep}, {/sep} {* separator between items *}
{/foreach}
Variables
{var $name = 'John'}
{var $items = [1, 2, 3]}
{default $lang = 'en'} {* only if not set *}
{capture $content}
<p>Captured HTML</p>
{/capture}
{$content}
Template Inheritance
Layout template (@layout.latte):
<!DOCTYPE html>
<html>
<head>
<title>{block title}Default{/block}</title>
</head>
<body>
{block content}{/block}
</body>
</html>
Child template:
{layout '@layout.latte'}
{block title}My Page{/block}
{block content}
<h1>Welcome</h1>
<p>Content here</p>
{/block}
Including Templates
{include 'header.latte'}
{include 'item.latte', item: $item, showPrice: true}
{include $dynamicTemplate}
Blocks
{block sidebar}
<aside>Sidebar content</aside>
{/block}
{include sidebar} {* print block *}
{include sidebar from 'other.latte'} {* from another file *}
{* Reusable definitions with parameters *}
{define button, $text, $type = 'primary'}
<button class="btn btn-{$type}">{$text}</button>
{/define}
{include button, 'Submit'}
{include button, 'Cancel', 'secondary'}
Common Tags Reference
| Tag | Description |
|---|
{$var} | Print escaped variable |
{if}...{/if} | Condition |
{foreach}...{/foreach} | Loop |
{var $x = ...} | Create variable |
{include 'file'} | Include template |
{block name}...{/block} | Define block |
{layout 'file'} | Extend layout |
{do expression} | Execute without output |
{php expression} | Execute PHP expression |
{dump $var} | Debug dump (Tracy) |
See the complete tag reference for all available tags.
Smart HTML Attributes
{* null removes attribute *}
<div title={$title}>
{* boolean controls presence *}
<input type="checkbox" checked={$isChecked}>
{* arrays in class *}
<div class={['btn', active => $isActive]}>
{* arrays JSON-encoded in data- *}
<div data-config={[theme: dark, count: 5]}>
n:class Helper
{foreach $items as $item}
<a n:class="$item->active ? active, $iterator->first ? first, item">
{$item->name}
</a>
{/foreach}
Latte in Nette Applications
Template Organization Strategy
Keep templates with presenters:
Product/
├── ProductPresenter.php
├── default.latte
├── edit.latte
└── detail.latte
Layout placement follows presenter organization:
Admin/
├── @layout.latte ← Admin-wide layout
├── Auth/
│ ├── @layout.latte ← Auth-specific layout
│ └── AuthPresenter.php
└── Catalog/
└── Product/
├── ProductPresenter.php
└── edit.latte
Template Partial Patterns
Shared template parts use @ prefix:
@layout.latte - layout templates@form.latte - reusable form structures@item.latte - list item templates
Passing Variables to Templates
The standard way is assigning to $this->template:
$this->template->article = $this->articles->getById($id);
For properties that should always be available in templates, use the #[TemplateVariable] attribute (requires public or protected visibility) instead of repeating assignments in every action:
use Nette\Application\Attributes\TemplateVariable;
class ArticlePresenter extends Nette\Application\UI\Presenter
{
#[TemplateVariable]
public string $siteName = 'My blog';
}
The property value is automatically passed as $siteName in every template. If you explicitly assign $this->template->siteName in an action, the explicit value wins.
Template Class Strategy
Create template classes for complex presenters:
class ProductPresenter extends BasePresenter
{
}
class ProductTemplate extends Nette\Bridges\ApplicationLatte\Template
{
public ProductRow $product;
public array $variants;
public ?CategoryRow $category;
}
When to use template classes:
- Presenters with 5+ template variables
- Complex data structures passed to templates
- When you want full IDE support in templates
Template Type Declaration:
{templateType App\Presentation\Product\ProductTemplate}
<h1>{$product->name}</h1>
{foreach $variants as $variant}
<div class="variant">{$variant->name} - {$variant->price}</div>
{/foreach}
Nette-specific Tags
{* Links *}
<a n:href="Product:detail $id">Detail</a>
<a href={link Product:detail $id}>Detail</a>
<a href={plink //Product:detail $id}>Absolute</a>
{* Components *}
{control productForm}
{control dataGrid}
{* AJAX Snippets *}
{snippet items}
{foreach $items as $item}
<div>{$item->name}</div>
{/foreach}
{/snippet}
{* Forms *}
{form loginForm}
{label username}{input username}
{label password}{input password}
{input submit}
{/form}
{* Assets (Nette Assets) *}
{asset 'admin.js'}
{asset 'front.css'}
Extension and Customization
Create single extension for entire application:
final class LatteExtension extends Latte\Extension
{
public function getFilters(): array
{
return [
'money' => fn($amount) => number_format($amount, 0, ',', ' ') . ' Kč',
];
}
public function getFunctions(): array
{
return [
'canEdit' => fn($entity) => $this->user->isAllowed($entity, 'edit'),
];
}
}
Register in config:
latte:
strictParsing: yes
extensions:
- App\Presentation\Accessory\LatteExtension
Enable strictParsing to catch template errors early (missing variables, typos in tag names).
Anti-Patterns to Avoid
- Don't put business logic in templates – templates display data, they don't process it. Calculations, filtering, and data transformations belong in presenters or services. Complex template logic is a sign that the presenter's
render* method isn't preparing data well enough.
- Don't create deep template hierarchies – more than 2 levels of
{layout} inheritance becomes hard to debug. Prefer {include} and {define} for composition over deep inheritance chains.
- Don't duplicate template code – if the same HTML structure appears in multiple templates, extract it to a
{define} block or a partial template (@item.latte). Duplication causes inconsistency when one copy gets updated but not the others.
Online Documentation
For detailed information, use WebFetch on these URLs:
