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.\" ========================================================================
.\"
.IX Title "Array::Iterator::BiDirectional 3pm"
.TH Array::Iterator::BiDirectional 3pm "2013-09-18" "perl v5.20.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
Array::Iterator::BiDirectional \- A subclass of Array::Iterator to allow forwards and backwards iteration
.SH "VERSION"
.IX Header "VERSION"
version 0.11
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  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 = $i\->get_previous();
\&      }
\&  }
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Occasionally it is useful for an iterator to go in both directions, forward and backward. One example would be token processing. When looping though tokens it is sometimes necessary to advance forward looking for a match to a rule. If the match fails, a bi-directional iterator can be moved back so that the next rule can be tried.
.SH "METHODS"
.IX Header "METHODS"
This is a subclass of Array::Iterator, only those methods that have been added are documented here, refer to the Array::Iterator documentation for more information.
.IP "\fBhas_previous([$n])\fR" 4
.IX Item "has_previous([$n])"
This method works much like \f(CW\*(C`hasNext\*(C'\fR does, it will return true (\f(CW1\fR) unless the beginning of the array has been reached, and false (\f(CW0\fR) otherwise.
.Sp
Optional argument has the same meaning except that it specifies \f(CW$n\fRth previous element.
.IP "\fBprevious\fR" 4
.IX Item "previous"
This method is much like \f(CW\*(C`next\*(C'\fR. It will return the previous item in the iterator, and throw an exception if it attempts to reach past the beginning of the array.
.IP "\fBget_previous\fR" 4
.IX Item "get_previous"
This method is much like \f(CW\*(C`get_next\*(C'\fR. It will return the previous item in the iterator, and return undef if it attempts to reach past the beginning of the array.
.IP "\fBlook_back([$n])\fR" 4
.IX Item "look_back([$n])"
This is the counterpart to \f(CW\*(C`peek\*(C'\fR, it will return the previous items in the iterator, but will not affect the internal counter.
.Sp
Optional argument has the same meaning except that it specifies \f(CW$n\fRth previous element.
.SH "BUGS"
.IX Header "BUGS"
None that I am aware of, if you find a bug, let me know, and I will be sure to fix it.
.SH "CODE COVERAGE"
.IX Header "CODE COVERAGE"
See the \fB\s-1CODE COVERAGE\s0\fR section of the \fBArray::Iterator\fR documentation for information about the code coverage of this module's test suite.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
This is a subclass of \fBArray::Iterator\fR, please refer to it for more documenation.
.SH "ORIGINAL AUTHOR"
.IX Header "ORIGINAL AUTHOR"
stevan little, <stevan@iinteractive.com>
.SH "ORIGINAL COPYRIGHT AND LICENSE"
.IX Header "ORIGINAL COPYRIGHT AND LICENSE"
Copyright 2004 by Infinity Interactive, Inc.
.PP
<http://www.iinteractive.com>
.PP
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
.SH "AUTHOR"
.IX Header "AUTHOR"
Steven Haryanto <stevenharyanto@gmail.com>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This software is copyright (c) 2013 by Steven Haryanto.
.PP
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.