WP_Style_Engine_Processor
Compiles styles from stores or collections of CSS rules into a stylesheet.
Source: wp-includes/style-engine/class-wp-style-engine-processor.php
Since: 6.1.0
Properties
| Property | Type | Visibility | Description |
|---|---|---|---|
$stores | array | protected | Collection of WP_Style_Engine_CSS_Rules_Store objects |
$css_rules | array | protected | Set of WP_Style_Engine_CSS_Rule objects to process |
Methods
add_store()
Adds a store to the processor.
php
public function add_store( WP_Style_Engine_CSS_Rules_Store $store ): WP_Style_Engine_ProcessorParameters
| Parameter | Type | Description |
|---|---|---|
$store | WP_Style_Engine_CSS_Rules_Store | Store to add |
Returns
$this for method chaining.
Notes
Triggers _doing_it_wrong() if $store is not a WP_Style_Engine_CSS_Rules_Store instance.
Example
php
$processor = new WP_Style_Engine_Processor();
$store = WP_Style_Engine_CSS_Rules_Store::get_store( 'my-context' );
$processor->add_store( $store );add_rules()
Adds rules to be processed.
php
public function add_rules(
WP_Style_Engine_CSS_Rule|WP_Style_Engine_CSS_Rule[] $css_rules
): WP_Style_Engine_ProcessorSince: 6.1.0
Since: 6.6.0 Added support for rules_group
Parameters
| Parameter | Type | Description |
|---|---|---|
$css_rules | WP_Style_Engine_CSS_Rule|array | Single rule or array of rules |
Returns
$this for method chaining.
Behavior
- Rules with the same selector are merged (declarations combined)
- Rules with a
rules_groupare keyed by"$rules_group $selector"to maintain separation - Existing rules are updated with new declarations rather than duplicated
Example
php
$processor = new WP_Style_Engine_Processor();
// Add single rule
$processor->add_rules( new WP_Style_Engine_CSS_Rule( '.a', array( 'color' => 'red' ) ) );
// Add multiple rules
$processor->add_rules( array(
new WP_Style_Engine_CSS_Rule( '.b', array( 'color' => 'blue' ) ),
new WP_Style_Engine_CSS_Rule( '.c', array( 'color' => 'green' ) ),
) );
// Merge declarations into existing selector
$processor->add_rules( new WP_Style_Engine_CSS_Rule( '.a', array( 'font-size' => '16px' ) ) );
// .a now has both color:red and font-size:16pxget_css()
Gets the compiled CSS string.
php
public function get_css( array $options = array() ): stringSince: 6.1.0
Since: 6.4.0 Optimization no longer the default
Parameters
| Parameter | Type | Description |
|---|---|---|
$options | array | Configuration options |
Options
| Key | Type | Default | Description |
|---|---|---|---|
optimize | bool | false | Combine rules with identical declarations |
prettify | bool | SCRIPT_DEBUG | Add newlines and indentation |
Returns
Compiled CSS string.
Process
- Collects rules from all added stores
- If
optimizeis true, combines selectors with identical declarations - Compiles each rule to CSS
- Concatenates all rules
Example
php
$processor = new WP_Style_Engine_Processor();
$processor->add_rules( array(
new WP_Style_Engine_CSS_Rule( '.a', array( 'color' => 'red' ) ),
new WP_Style_Engine_CSS_Rule( '.b', array( 'color' => 'red' ) ),
new WP_Style_Engine_CSS_Rule( '.c', array( 'font-size' => '16px' ) ),
) );
// Without optimization
echo $processor->get_css();
// Output: '.a{color:red}.b{color:red}.c{font-size:16px}'
// With optimization (combine .a and .b)
echo $processor->get_css( array( 'optimize' => true ) );
// Output: '.a,.b{color:red}.c{font-size:16px}'
// Prettified
echo $processor->get_css( array( 'prettify' => true ) );
// Output:
// .a {
// color: red;
// }
// .b {
// color: red;
// }
// .c {
// font-size: 16px;
// }Private Methods
combine_rules_selectors()
Combines selectors from rules when they have identical declarations.
php
private function combine_rules_selectors(): voidBehavior
- Serializes each rule’s declarations to JSON for comparison
- Finds rules with identical declaration sets
- Merges their selectors (comma-separated)
- Removes duplicate rules, keeping combined version
Example Effect
Before:
css
.a { color: red; }
.b { color: red; }
.c { color: blue; }After optimization:
css
.a, .b { color: red; }
.c { color: blue; }