Hash-SafeKeys

Every hash variable in Perl has its own internal iterator,
accessed by the builtin C<each>, C<keys>, and C<values>
functions. The iterator is also implicitly used whenever
the hash is evaluated in list context.  The iterator is
"reset" whenever C<keys> or C<values> is called on a hash,
including the implicit calls when the hash is evaluated in
list context. That makes it dangerous to do certain hash
operations inside a C<while ... each> loop:

    while (my($k,$v) = each %hash) {
       ...
       @k = sort keys %hash;               # Infinite loop!
       @v = grep { /foo/ }, values %hash;  # Ack!
       print join ' ', %hash;              # Run away!
    }

C<Hash::SafeKeys> provides alternate functions to access
the keys, values, or entire contents of a hash in a way
that does not reset the iterator, making them safe to use
in such contexts:

    while (my($k,$v) = each %hash) {
       ...
       @k = sort safekeys %hash;               # Can do
       @v = grep { /foo/ }, safevalues %hash;  # No problem
       print join ' ', safecopy %hash;         # Right away, sir
    }


INSTALLATION

To install this module, run the following commands:

	perl Makefile.PL
	make
	make test
	make install

SUPPORT AND DOCUMENTATION

After installing, you can find documentation for this module with the
perldoc command.

    perldoc Hash::SafeKeys

You can also look for information at:

    RT, CPAN's request tracker (report bugs here)
        http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-SafeKeys

    AnnoCPAN, Annotated CPAN documentation
        http://annocpan.org/dist/Hash-SafeKeys

    CPAN Ratings
        http://cpanratings.perl.org/d/Hash-SafeKeys

    Search CPAN
        http://search.cpan.org/dist/Hash-SafeKeys/


LICENSE AND COPYRIGHT

Copyright (C) 2012-2016 Marty O'Brien

This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.