yaml-php-callbacks-php-emit-7

  • Callbacks

    • Emit callbacks

  • Emit callbacks

    • Emit callbacks

    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.

    Example #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);
    ?>

    The above example will output something similar to:

    string(43) "---
example: !example/emit
- a
- b
- c
...
"