1oometa(n) Data registry for TclOO frameworks oometa(n)
2______________________________________________________________________________
6
8 oometa - oo::meta A data registry for classess
9
11 oo::meta::info
12 oo::meta::info branchget ?key? ?...?
14 oo::meta::info branchset ?key...? key value
16 oo::meta::info dump class
18 oo::meta::info class is type ?args?
20 oo::meta::info class merge ?dict? ?dict? ?...?
22 oo::meta::info class rebuild
24 oo::meta::metadata class
26 oo::define meta
28 oo::class method meta
30 oo::object method meta
32 oo::object method meta cget ?field? ?...? field
34______________________________________________________________________________
36
38 The oo::meta package provides a data registry service for TclOO
39 classes.
40
42 oo::class create animal {
43 meta set biodata animal: 1
44 }
45 oo::class create mammal {
46 superclass animal
47 meta set biodata mammal: 1
48 }
49 oo::class create cat {
50 superclass mammal
51 meta set biodata diet: carnivore
52 }
53 cat create felix
55 puts [felix meta dump biodata]
56 > animal: 1 mammal: 1 diet: carnivore
57 felix meta set biodata likes: {birds mice}
59 puts [felix meta get biodata]
60 > animal: 1 mammal: 1 diet: carnivore likes: {bird mice}
61 # Modify a class
63 mammal meta set biodata metabolism: warm-blooded
64 puts [felix meta get biodata]
65 > animal: 1 mammal: 1 metabolism: warm-blooded diet: carnivore likes: {birds mice}
66 # Overwrite class info
68 felix meta set biodata mammal: yes
69 puts [felix meta get biodata]
70 > animal: 1 mammal: yes metabolism: warm-blooded diet: carnivore likes: {birds mice}
71
74 The concept behind oo::meta is that each class contributes a snippet of
75 local data. When oo::meta::metadata is called, the system walks
76 through the linear ancestry produced by oo::meta::ancestors, and recur‐
77 sively combines all of that local data for all of a class' ancestors
78 into a single dict. Instances of oo::object can also combine class
79 data with a local dict stored in the meta variable.
80
82 oo::meta::info
83 oo::meta::info is intended to work on the metadata of a class in
84 a manner similar to if the aggregate pieces where assembled into
85 a single dict. The system mimics all of the standard dict com‐
86 mands, and addes the following:
87 oo::meta::info branchget ?key? ?...?
89 Returns a dict representation of the element at args, but with
90 any trailing : removed from field names.
91 ::oo::meta::info $myclass set option color {default: green widget: colorselect}
94 puts [::oo::meta::info $myclass get option color]
95 > {default: green widget: color}
96 puts [::oo::meta::info $myclass branchget option color]
97 > {default green widget color}
98 oo::meta::info branchset ?key...? key value
101 Merges dict with any other information contaned at node
102 ?key...?, and adding a trailing : to all field names.
103 ::oo::meta::info $myclass branchset option color {default green widget colorselect}
106 puts [::oo::meta::info $myclass get option color]
107 > {default: green widget: color}
108 oo::meta::info dump class
111 Returns the complete snapshot of a class metadata, as producted
112 by oo::meta::metadata
113 oo::meta::info class is type ?args?
115 Returns a boolean true or false if the element ?args? would
116 match string is type value
117 ::oo::meta::info $myclass set constant mammal 1
120 puts [::oo::meta::info $myclass is true constant mammal]
121 > 1
122 oo::meta::info class merge ?dict? ?dict? ?...?
125 Combines all of the arguments into a single dict, which is then
126 stored as the new local representation for this class.
127 oo::meta::info class rebuild
129 Forces the meta system to destroy any cached representation of a
130 class' metadata before the next access to oo::meta::metadata
131 oo::meta::metadata class
133 Returns an aggregate picture of the metadata for class, combin‐
134 ing its local data with the local data from its ancestors.
135 oo::define meta
137 The package injects a command oo::define::meta which works to
138 provide a class in the process of definition access to
139 oo::meta::info, but without having to look the name up.
140 oo::define myclass {
143 meta set foo bar: baz
144 }
145 oo::class method meta
148 The package injects a new method meta into oo::class which works
149 to provide a class instance access to oo::meta::info.
150 oo::object method meta
152 The package injects a new method meta into oo::object.
153 oo::object combines the data for its class (as provided by
154 oo::meta::metadata), with a local variable meta to produce a
155 local picture of metadata. This method provides the following
156 additional commands:
157 oo::object method meta cget ?field? ?...? field
159 Attempts to locate a singlar leaf, and return its value. For
160 single option lookups, this is faster than my meta getnull
161 ?field? ?...? field], because it performs a search instead
162 directly instead of producing the recursive merge product
163 between the class metadata, the local meta variable, and THEN
164 performing the search.
165
167 This document, and the package it describes, will undoubtedly contain
168 bugs and other problems. Please report such in the category tcloo of
169 the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please
170 also report any ideas for enhancements you may have for either package
171 and/or documentation.
172 When proposing code changes, please provide unified diffs, i.e the out‐
174 put of diff -u.
175 Note further that attachments are strongly preferred over inlined
177 patches. Attachments can be made by going to the Edit form of the
178 ticket immediately after its creation, and then using the left-most
179 button in the secondary navigation bar.
180
182 TOOL, TclOO
183
185 TclOO
186
188 Copyright (c) 2015 Sean Woods <yoda@etoyoc.com>
189tcllib 0.7.1 oometa(n)