Config::Model::Role::Grab - Role to grab data from elsewhere in the tree
$root->grab(steps => 'foo:2 bar');
$root->grab(steps => 'foo:2 bar', type => 'leaf');
$root->grab_value(steps => 'foo:2 bar');
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).
Grab an object from the configuration tree.
- "steps" (or "step")
- A string indicating the steps to follow in the tree to find
the required item. (mandatory)
- 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")
- 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)
$root->grab(steps => 'foo:2 bar', type => 'leaf')
$root->grab(steps => 'foo:2 bar', type => ['leaf','check_list'])
- When set to 1, "hash" or "list"
configuration element are created when requested by the passed steps.
(default is 1).
- 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
The "steps" parameters is made of the following items separated by
- Go up one node
- Go to the root node.
- 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.
- Go down using "xxx" element.
- Go down using "xxx" element and id "yy"
(valid for hash or list elements)
- 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.
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.
Like "grab", but returns the annotation of an object.
Returns the root of the configuration tree.
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.
# returns a Config::Model::Node object for a Systemd::Service config class
This software is Copyright (c) 2005-2017 by Dominique Dumont.
This is free software, licensed under:
The GNU Lesser General Public License, Version 2.1, February 1999