NAME

       Config::Model::Role::Grab - Role to grab data from elsewhere in the tree

VERSION

       version 2.117

SYNOPSIS

         $root->grab('foo:2 bar');
         $root->grab(steps => 'foo:2 bar');
         $root->grab(steps => 'foo:2 bar', type => 'leaf');
         $root->grab_value(steps => 'foo:2 bar');

DESCRIPTION

       Role used to let a tree item (i.e. node, hash, list or leaf) to grab another item or value
       from the configuration tree using a path (a bit like an xpath path with a different
       syntax).

METHODS

   grab
       Grab an object from the configuration tree.

       Parameters are:

       "steps" (or "step")
           A string indicating the steps to follow in the tree to find the required item.
           (mandatory)

       "mode"
           When set to "strict", "grab" throws an exception if no object is found using the
           passed string. When set to "adaptative", the object found last is returned. For
           instance, for the steps "good_step wrong_step", only the object held by "good_step" is
           returned. When set to "loose", grab returns undef in case of problem. (default is
           "strict")

       "type"
           Either "node", "leaf", "hash" or "list" or an array ref containing these values.
           Returns only an object of requested type. Depending on "strict" value, "grab" either
           throws an exception or returns the last object found with the requested type.
           (optional, default to "undef", which means any type of object)

           Examples:

            $root->grab(steps => 'foo:2 bar', type => 'leaf')
            $root->grab(steps => 'foo:2 bar', type => ['leaf','check_list'])

       "autoadd"
           When set to 1, "hash" or "list" configuration element are created when requested by
           the passed steps. (default is 1).

       grab_non_available
           When set to 1, grab returns an object even if this one is not available. I.e. even if
           this element was warped out. (default is 0).

       The "steps" parameters is made of the following items separated by spaces:

       -       Go up one node

       !       Go to the root node.

       !Foo    Go up the configuration tree until the "Foo" configuration class is found. Raise
               an exception if no "Foo" class is found when root node is reached.

       xxx     Go down using "xxx" element.

       xxx:yy  Go down using "xxx" element and id "yy" (valid for hash or list elements)

       ?xxx    Go up the tree until a node containing element "xxx" is found. Then go down the
               tree like item "xxx".

               If "?xxx:yy", go up the tree the same way. But no check is done to see if id "yy"
               actually exists or not. Only the element "xxx" is considered when going up the
               tree.

   grab_value
       Like "grab", but returns the value of a leaf or check_list object, not just the leaf
       object.

       "grab_value" raises an exception if following the steps ends on anything but a leaf or a
       check_list.

   grab_annotation
       Like "grab", but returns the annotation of an object.

   grab_root
       Returns the root of the configuration tree.

   grab_ancestor
       Parameter: a configuration class name

       Go up the configuration tree until a node using the configuration class is found. Returns
       the found node or undef.

       Example:

         # returns a Config::Model::Node object for a Systemd::Service config class
         $self->grab('Systemd::Service');

AUTHOR

       Dominique Dumont

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2005-2018 by Dominique Dumont.

       This is free software, licensed under:

         The GNU Lesser General Public License, Version 2.1, February 1999