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oometa(n) Data registry for TclOO frameworks oometa(n) 





NAME


oometa - oo::meta A data registry for classess






SYNOPSIS


oo::meta::info


oo::meta::info branchget ?key? ?...?


oo::meta::info branchset ?key...? key
    value


oo::meta::info dump class


oo::meta::info class is type
    ?args?


oo::meta::info class merge ?dict?
    ?dict? ?...?


oo::meta::info class rebuild


oo::meta::metadata class


oo::define meta


oo::class method meta


oo::object method meta


oo::object method meta cget ?field? ?...?
    field










DESCRIPTION


The oo::meta package provides a data registry service for
    TclOO classes.






USAGE




oo::class create animal {


  meta set biodata animal: 1
}
oo::class create mammal {


  superclass animal


  meta set biodata mammal: 1
}
oo::class create cat {


  superclass mammal


  meta set biodata diet: carnivore
}
cat create felix
puts [felix meta dump biodata]
> animal: 1 mammal: 1 diet: carnivore
felix meta set biodata likes: {birds mice}
puts [felix meta get biodata]
> animal: 1 mammal: 1 diet: carnivore likes: {bird mice}
# Modify a class
mammal meta set biodata metabolism: warm-blooded
puts [felix meta get biodata]
> animal: 1 mammal: 1 metabolism: warm-blooded diet: carnivore likes: {birds mice}
# Overwrite class info
felix meta set biodata mammal: yes
puts [felix meta get biodata]
> animal: 1 mammal: yes metabolism: warm-blooded diet: carnivore likes: {birds mice}









CONCEPT


The concept behind oo::meta is that each class contributes
    a snippet of local data. When oo::meta::metadata is called,
    the system walks through the linear ancestry produced by
    oo::meta::ancestors, and recursively combines all of that local data
    for all of a class' ancestors into a single dict. Instances of oo::object
    can also combine class data with a local dict stored in the meta
    variable.






COMMANDS



  

  
oo::meta::info is intended to work on the metadata of a class in a
      manner similar to if the aggregate pieces where assembled into a single
      dict. The system mimics all of the standard dict commands, and addes the
      following:

  

  
Returns a dict representation of the element at args, but with any
      trailing : removed from field names.






::oo::meta::info $myclass set option color {default: green widget: colorselect}
puts [::oo::meta::info $myclass get option color]
> {default: green widget: color}
puts [::oo::meta::info $myclass branchget option color]
> {default green widget color}






  

  
Merges dict with any other information contaned at node
      ?key...?, and adding a trailing : to all field names.






::oo::meta::info $myclass branchset option color {default green widget colorselect}
puts [::oo::meta::info $myclass get option color]
> {default: green widget: color}






  

  
Returns the complete snapshot of a class metadata, as producted by
      oo::meta::metadata

  

  
Returns a boolean true or false if the element ?args? would match
      string is type value






::oo::meta::info $myclass set constant mammal 1
puts [::oo::meta::info $myclass is true constant mammal]
> 1






  

  
Combines all of the arguments into a single dict, which is then stored as
      the new local representation for this class.

  

  
Forces the meta system to destroy any cached representation of a class'
      metadata before the next access to oo::meta::metadata

  

  
Returns an aggregate picture of the metadata for class, combining
      its local data with the local data from its ancestors.

  

  
The package injects a command oo::define::meta which works to
      provide a class in the process of definition access to
      oo::meta::info, but without having to look the name up.






oo::define myclass {


  meta set foo bar: baz
}






  

  
The package injects a new method meta into oo::class which
      works to provide a class instance access to oo::meta::info.

  

  
The package injects a new method meta into oo::object.
      oo::object combines the data for its class (as provided by
      oo::meta::metadata), with a local variable meta to produce a
      local picture of metadata. This method provides the following additional
      commands:

  

  
Attempts to locate a singlar leaf, and return its value. For single option
      lookups, this is faster than my meta getnull ?field?
      ?...? field], because it performs a search instead directly
      instead of producing the recursive merge product between the class
      metadata, the local meta variable, and THEN performing the
    search.








BUGS, IDEAS, FEEDBACK


This document, and the package it describes, will undoubtedly
    contain bugs and other problems. Please report such in the category
    tcloo of the Tcllib Trackers
    [http://core.tcl.tk/tcllib/reportlist]. Please also report any ideas for
    enhancements you may have for either package and/or documentation.


When proposing code changes, please provide unified diffs,
    i.e the output of diff -u.


Note further that attachments are strongly preferred over
    inlined patches. Attachments can be made by going to the Edit form of
    the ticket immediately after its creation, and then using the left-most
    button in the secondary navigation bar.






KEYWORDS


TOOL, TclOO






CATEGORY


TclOO






COPYRIGHT


Copyright (c) 2015 Sean Woods <yoda@etoyoc.com>








  

    0.7.1
    tcllib