Emit callbacks
Emit callbacks are invoked when an instance of a registered class is
emitted by yaml_emit() or
yaml_emit_file(). The callback is passed the object to
be emitted. The callback must return an array having two keys:
"tag
" and "data
".
The value associated with the "tag
" key must
be a string to be used as the YAML tag in the output. The value associated
with the "data
" key will be encoded as YAML
and emitted in place of the intercepted object.
Beispiel #1 Emit callback example
<?php
class EmitExample {
public $data; // data may be in any pecl/yaml suitable type
public function __construct ($d) {
$this->data = $d;
}
/**
* Yaml emit callback function, referred on yaml_emit call by class name.
*
* Expected to return an array with 2 values:
* - 'tag': custom tag for this serialization
* - 'data': value to convert to yaml (array, string, bool, number)
*
* @param object $obj Object to be emitted
* @return array Tag and surrogate data to emit
*/
public static function yamlEmit (EmitExample $obj) {
return array(
'tag' => '!example/emit',
'data' => $obj->data,
);
}
}
$emit_callbacks = array(
'EmitExample' => array('EmitExample', 'yamlEmit')
);
$t = new EmitExample(array('a','b','c'));
$yaml = yaml_emit(
array(
'example' => $t,
),
YAML_ANY_ENCODING,
YAML_ANY_BREAK,
$emit_callbacks
);
var_dump($yaml);
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
string(43) "--- example: !example/emit - a - b - c ... "