public function traverse(callable $visitor)
    {
        if ($this->_query) {
            return;
        }

        if (!$this->_castedExpressions) {
            $this->_processExpressions();
        }

        foreach ($this->_values as $v) {
            if ($v instanceof ExpressionInterface) {
                $v->traverse($visitor);
            }
            if (!is_array($v)) {
                continue;
            }
            foreach ($v as $column => $field) {
                if ($field instanceof ExpressionInterface) {
                    $visitor($field);
                    $field->traverse($visitor);
                }
            }
        }
    }
public function traverse(callable $visitor)
    {
        if ($this->_query) {
            return;
        }

        if (!$this->_castedExpressions) {
            $this->_processExpressions();
        }

        foreach ($this->_values as $v) {
            if ($v instanceof ExpressionInterface) {
                $v->traverse($visitor);
            }
            if (!is_array($v)) {
                continue;
            }
            foreach ($v as $column => $field) {
                if ($field instanceof ExpressionInterface) {
                    $visitor($field);
                    $field->traverse($visitor);
                }
            }
        }
    }
public function traverse ( callable $ visitor ) { if ( $ this -> _query ) { return ; } if ( ! $ this -> _castedExpressions ) { $ this -> _processExpressions ( ) ; } foreach ( $ this -> _values as $ v ) { if ( $ v instanceof ExpressionInterface ) { $ v -> traverse ( $ visitor ) ; } if ( ! is_array ( $ v ) ) { continue ; } foreach ( $ v as $ column => $ field ) { if ( $ field instanceof ExpressionInterface ) { $ visitor ( $ field ) ; $ field -> traverse ( $ visitor ) ; } } } }
Traverse the values expression.

This method will also traverse any queries that are to be used in the INSERT
values.

@param callable $visitor The visitor to traverse the expression with.
@return void
Traverse the values expression .