.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. 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Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Array::Iterator::BiDirectional 3pm" .TH Array::Iterator::BiDirectional 3pm "2019-11-02" "perl v5.30.0" "User Contributed Perl Documentation" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Array::Iterator::BiDirectional \- A subclass of Array::Iterator to allow forwards and backwards iteration .SH "VERSION" .IX Header "VERSION" This document describes version 0.12 of Array::Iterator::BiDirectional (from Perl distribution Array-Iterator), released on 2017\-07\-04. .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 = $i\->get_previous(); \& } \& } .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" Occasionally it is useful for an iterator to go in both directions, forward and backward. One example would be token processing. When looping though tokens it is sometimes necessary to advance forward looking for a match to a rule. If the match fails, a bi-directional iterator can be moved back so that the next rule can be tried. .SH "ORIGINAL AUTHOR" .IX Header "ORIGINAL AUTHOR" stevan little, .SH "ORIGINAL COPYRIGHT AND LICENSE" .IX Header "ORIGINAL COPYRIGHT AND LICENSE" Copyright 2004 by Infinity Interactive, Inc. .PP .PP This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. .SH "METHODS" .IX Header "METHODS" This is a subclass of Array::Iterator, only those methods that have been added are documented here, refer to the Array::Iterator documentation for more information. .IP "\fBhas_previous([$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 "HOMEPAGE" .IX Header "HOMEPAGE" Please visit the project's homepage at . .SH "SOURCE" .IX Header "SOURCE" Source repository is at . .SH "BUGS" .IX Header "BUGS" Please report any bugs or feature requests on the bugtracker website .PP When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature. .SH "SEE ALSO" .IX Header "SEE ALSO" This is a subclass of \fBArray::Iterator\fR, please refer to it for more documenation. .SH "AUTHOR" .IX Header "AUTHOR" perlancar .SH "COPYRIGHT AND LICENSE" .IX Header "COPYRIGHT AND LICENSE" This software is copyright (c) 2017, 2013, 2012, 2011 by perlancar@cpan.org. .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.