NAME¶
Array::Iterator::BiDirectional - A subclass of Array::Iterator to allow forwards
and backwards iteration
VERSION¶
version 0.11
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 = $i->get_next();
# ...
if ($something_happens) {
# back up the iterator
$current = $i->get_previous();
}
}
DESCRIPTION¶
Occasionally it is useful for an iterator to go in both directions, forward and
backward. One example would be token processing. When looping though tokens it
is sometimes necessary to advance forward looking for a match to a rule. If
the match fails, a bi-directional iterator can be moved back so that the next
rule can be tried.
METHODS¶
This is a subclass of Array::Iterator, only those methods that have been added
are documented here, refer to the Array::Iterator documentation for more
information.
- has_previous([$n])
- This method works much like "hasNext" does, it will return true
(1) unless the beginning of the array has been reached, and false (0)
otherwise.
Optional argument has the same meaning except that it specifies $nth
previous element.
- previous
- This method is much like "next". It will return the previous
item in the iterator, and throw an exception if it attempts to reach past
the beginning of the array.
- get_previous
- This method is much like "get_next". It will return the previous
item in the iterator, and return undef if it attempts to reach past the
beginning of the array.
- look_back([$n])
- This is the counterpart to "peek", it will return the previous
items in the iterator, but will not affect the internal counter.
Optional argument has the same meaning except that it specifies $nth
previous element.
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.
ORIGINAL AUTHOR¶
stevan little, <stevan@iinteractive.com>
ORIGINAL 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.
AUTHOR¶
Steven Haryanto <stevenharyanto@gmail.com>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2013 by Steven Haryanto.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.