Config::Model::IdElementReference(3pm)

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NAME

6       Config::Model::IdElementReference - Refer to id element(s) and extract
7       keys
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VERSION

10       version 1.205
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SYNOPSIS

13        # used from a value class
14        element => [
15                   node_host => { type => 'leaf',
16                                  value_type => 'reference' ,
17                                  refer_to => '! host'
18                                },
19                   if   => { type => 'leaf',
20                             value_type => 'reference' ,
21                             computed_refer_to
22                             => { formula => '  ! host:$h if ',
23                                  variables => { h => '- node_host' }
24                                }
25                           },
26                   ],
27
28         # used from checklist
29         element => [
30                     # simple reference, checklist items are given by the
31                     # keys of my_hash
32                     refer_to_list => { type => 'check_list',
33                                        refer_to => '- my_hash'
34                                      },
35
36                     # checklist items are given by combining my_hash*
37                     refer_to_2_list
38                                   => { type => 'check_list',
39                                        refer_to => '- my_hash + - my_hash2   + - my_hash3'
40                                      },
41                    ]
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DESCRIPTION

44       This class is user by Config::Model::Value to set up an enumerated
45       value where the possible choice depends on the key of a
46       Config::Model::HashId or the content of a Config::Model::ListId object.
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48       This class is also used by Config::Model::CheckList to define the
49       cheklist items from the keys of another hash (or content of a list).
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CONSTRUCTOR

52       Construction is handled by the calling object.
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Config class parameters

55       refer_to
56           "refer_to" is used to specify a hash element that will be used as a
57           reference. "refer_to" points to an array or hash element in the
58           configuration tree using the path syntax (See "grab" in
59           Config::Model::Node for details).
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61       computed_refer_to
62           When "computed_refer_to" is used, the path is computed using values
63           from several elements in the configuration tree.
64           "computed_refer_to" is a hash with 2 mandatory elements: "formula"
65           and "variables".
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67       The available choice of this (computed or not) reference value is made
68       from the available keys of the refered_to hash element or the values of
69       the refered_to array element.
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71       The example means the the value must correspond to an existing host:
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73        value_type => 'reference',
74        refer_to => '! host'
75
76       This example means the the value must correspond to an existing lan
77       within the host whose Id is specified by hostname:
78
79        value_type => 'reference',
80        computed_refer_to => { formula => '! host:$a lan',
81                               variables => { a => '- hostname' }
82                             }
83
84       If you need to combine possibilities from several hash, use the ""+""
85       token to separate 2 paths:
86
87        value_type => 'reference',
88        computed_refer_to => { formula => '! host:$a lan + ! host:foobar lan',
89                               variables => { a => '- hostname' }
90                             }
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92       You can specify "refer_to" or "computed_refer_to" with a "choice"
93       argument so the possible enum value will be the combination of the
94       specified choice and the refered_to values.
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Methods

97   reference_info
98       Returns a human readable string with explains how is retrieved the
99       reference. This method is mostly used to construct an error messages.
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AUTHOR

102       Dominique Dumont, (ddumont at cpan dot org)
103