NAME

Array::Iterator::BiDirectional - A subclass of Array::Iterator to allow forwards and backwards iteration

SYNOPSIS

  use Array::Iterator::BiDirectional;
  
  # create an instance of the iterator
  my $i = Array::Iterator::BiDirectional->new(1 .. 100);
  
  while ($some_condition_exists) {
      # get the latest item from 
      # the iterator
      my $current = $i->getNext();
      # ...
      if ($something_happens) {
          # back up the iterator 
          $current = $i->getPrevious();
      }
  }

DESCRIPTION

Occasionally it is useful for an iterator to go in both directions, forward and backward. One example would be token processing. When looping though tokens it is sometimes necessary to advance forward looking for a match to a rule. If the match fails, a bi-directional iterator can be moved back so that the next rule can be tried.

METHODS

This is a subclass of Array::Iterator, only those methods that have been added are documented here, refer to the Array::Iterator documentation for more information.

hasPrevious

This method works much like isNext does, it will return true (1) unless the begining of the array has been reached, and false (0) otherwise.

previous

This method is much like next. It will return the previous item in the iterator, and throw an exception if it attempts to reach past the begining of the array.

getPrevious

This method is much like getNext. It will return the previous item in the iterator, and return undef if it attempts to reach past the begining of the array.

lookBack

This is the counterpart to peek, it will return the previous items in the iterator, but will not affect the internal counter.

BUGS

None that I am aware of, if you find a bug, let me know, and I will be sure to fix it.

CODE COVERAGE

See the CODE COVERAGE section of the Array::Iterator documentation for information about the code coverage of this module's test suite.

SEE ALSO

This is a subclass of Array::Iterator, please refer to it for more documenation.

AUTHOR

stevan little, <stevan@iinteractive.com>

COPYRIGHT AND LICENSE

Copyright 2004 by Infinity Interactive, Inc.

http://www.iinteractive.com

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.