public function EasyRdf_Collection::offsetUnset in Zircon Profile 8

Same name and namespace in other branches

1. 8.0 vendor/easyrdf/easyrdf/lib/EasyRdf/Collection.php \EasyRdf_Collection::offsetUnset()

Array Access: delete an item at a specific postion using array syntax

Example: unset($seq[2]);

File

vendor/easyrdf/easyrdf/lib/EasyRdf/Collection.php, line 293

Class

EasyRdf_Collection

Sub-class of EasyRdf_Resource that represents an RDF collection (rdf:List)

Code

public function offsetUnset($offset) {
  if (is_int($offset) and $offset > 0) {
    list($node, $position) = $this
      ->getCollectionNode($offset);
  }
  else {
    throw new InvalidArgumentException("Collection offset must be a positive integer");
  }

  // Does the item exist?
  if ($node and $position === $offset) {
    $nil = $this->graph
      ->resource('rdf:nil');
    if ($position === 1) {
      $rest = $node
        ->get('rdf:rest');
      if ($rest and $rest !== $nil) {

        // Move second value, so we can keep the head of list
        $node
          ->set('rdf:first', $rest
          ->get('rdf:first'));
        $node
          ->set('rdf:rest', $rest
          ->get('rdf:rest'));
        $rest
          ->delete('rdf:first');
        $rest
          ->delete('rdf:rest');
      }
      else {

        // Just remove the value
        $node
          ->delete('rdf:first');
        $node
          ->delete('rdf:rest');
      }
    }
    else {

      // Remove the value and re-link the list
      $node
        ->delete('rdf:first');
      $rest = $node
        ->get('rdf:rest');
      $previous = $node
        ->get('^rdf:rest');
      if (is_null($rest)) {
        $rest = $nil;
      }
      if ($previous) {
        $previous
          ->set('rdf:rest', $rest);
      }
    }
  }
}