CXC::Data::Visitor

CXC::Data::Visitor provides a means of performing a depth first
traversal of a data structure. There are similar modules on CPAN ("SEE
ALSO"); this module provides a few extras.

*   Hashes are traversed in sorted key order. By default the order is
    that provided by Perl's standard string sort order. The caller may
    provide a coderef to provide an alternative sort order
    ("sort_keys").

*   The callback is invoked first on a container and then its elements.
    Given

      { a => { b => [ 0 ], c => 2 } }

    the callback order is

      {a}, {a}{b}, {a}{b}[0], {a}{c}

*   Blessed hashes or arrays are treated as terminal elements and are
    not further traversed.

*   Cycles are detected upon traversing a container a second time in a
    depth first search, and the resultant action is caller selectable.

*   Containers that can be reached multiple times without cycling, e.g.

      %hash = ( a => { b => 1 }, );
      $hash{c} = $hash{a};

    are visited once per parent, e.g.

      {a}, {a}{b}, {a}{b}[0]
      {c}, {c}{b}, {c}{b}[0]

*   A container (hash or array) may be optionally be immediately
    revisited.

*   An element whose value is a container may be optionally be revisited
    after the container is visited.

*   The traversal may be aborted.

*   The complete path from the structure route to an element (both the
    ancestor containers and the keys and indexes required to traverse
    the path) is available.

INSTALLATION

This is a Perl module distribution. It should be installed with whichever
tool you use to manage your installation of Perl, e.g. any of

  cpanm .
  cpan  .
  cpanp -i .

Consult http://www.cpan.org/modules/INSTALL.html for further instruction.
Should you wish to install this module manually, the procedure is

  perl Build.PL
  ./Build
  ./Build test
  ./Build install

COPYRIGHT AND LICENSE

This software is Copyright (c) 2024 by Smithsonian Astrophysical
Observatory.

This is free software, licensed under:

  The GNU General Public License, Version 3, June 2007