Andy Lester > List-Cycle-1.00 > List::Cycle

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Module Version: 1.00   Source   Latest Release: List-Cycle-1.02

NAME ^

List::Cycle - Objects for cycling through a list of values

VERSION ^

Version 1.00

SYNOPSIS ^

List::Cycle gives you an iterator object for cycling through a series of values. The canonical use is for cycling through a list of colors for alternating bands of color on a report.

    use List::Cycle;

    my $colors = List::Cycle->new( {values => ['#000000', '#FAFAFA', '#BADDAD']} );
    print $colors->next; # #000000
    print $colors->next; # #FAFAFA
    print $colors->next; # #BADDAD
    print $colors->next; # #000000
    print $colors->next; # #FAFAFA
    ... etc ...

You'd call it at the top of a loop:

    while ( ... ) {
        my $color = $colors->next;
        print qq{<tr bgcolor="$color">;
        ...
    }

Note that a List::Cycle object is not a standard Perl blessed hash. It's an inside-out object, as suggested in Perl Best Practices. In the five years since PBP has come out, inside-out objects have been almost universally ignored, but I keep List::Cycle as an example. If you don't care about the internals of the object, then List::Cycle is a fine module for you to use.

FUNCTIONS ^

new( {values => \@values} )

Creates a new cycle object, using @values.

The values keyword can be vals, if you like.

$cycle->set_values(\@values)

Sets the cycle values and resets the internal pointer.

$cycle->reset

Sets the internal pointer back to the beginning of the cycle.

    my $color = List::Cycle->new( {values => [qw(red white blue)]} );
    print $color->next; # red
    print $color->next; # white
    $color->reset;
    print $color->next; # red, not blue

$cycle->dump

Returns a handy string representation of internals.

$cycle->next

Gives the next value in the sequence.

AUTHOR ^

Andy Lester, <andy at petdance.com>

SUPPORT ^

You can find documentation for this module with the perldoc command.

    perldoc List::Cycle

You can also look for information at:

BUGS ^

Please report any bugs or feature requests to bug-list-cycle @ rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=List-Cycle. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

ACKNOWLEDGEMENTS ^

List::Cycle is a playground that uses some of the ideas in Damian Conway's marvelous Perl Best Practices. http://www.oreilly.com/catalog/perlbp/ One of the chapters mentions a mythical List::Cycle module, so I made it real.

Thanks also to Ricardo SIGNES and Todd Rinaldo for patches.

COPYRIGHT & LICENSE ^

Copyright 2005-2010 Andy Lester.

This program is free software; you can redistribute it and/or modify it under the terms of either:

1; # End of List::Cycle

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