History: Object References

            When creating object, auto-increment ids are used internally by Tiki. Object references allow to track these object IDs during the profile creation to create relationships between the different objects. For example, when a tracker is created, the trackerId provided to it is arbitrary. Unless you know what that ID is, it is impossible to add fields or items to it in an automated way. It could be possible to __force__ the ID to a certain value, but this could cause conflicts if multiple profiles decided to use the same value.

During profile installation, the ''ref:'' attribute names an object. When a named object is encountered, the ID assigned to it is stored under the provided name. Other objects can access this value as a variable for any of their attributes.

The ((object block)) contains all objects to be created.

!! Category Tree Profile
{CODE(caption=>YAML)}
objects:
 -
  type: category
  ref: profile_category
  data:
   name: Profiles
 - 
  type: category
  ref: app_category
  data:
   name: Tracker Applications
   parent: $profile_category
 -
  type: category
  data:
   name: Site Samples
   parent: $profile_category
{CODE}

As you can see, the profile defined here will create three distinct categories. ''Profiles'' will be the parent category and contain two child categories. These child categories find their parent by using a reference (__$''profile_category''__). This internal reference uses the name defined by the ''ref'' attribute. For more information about the category object type, see ((Category Handler)).

* Reference attributes (''ref'')
** are optional
** must be unique inside a profile
** can be useful to understand the ProfileHistory
* Internal references (__$''object_name''__)
** must refer to an existing object
** act as a variable
** must not cause circular dependencies between objects
* Inter-profile references (__$''ProfileName'':''object_name''__)
** must refer to an existing profile on the same site
** must not cause circular dependencies between profiles
** allow to refer to objects created by other profiles
** will cause the other profile to be installed
* Cross-site references (__$''example.com'':''ProfileName'':''object_name''__)
** must refer to a valid Tiki installation
** allows to create custom profile extensions on a personal host (see ((Custom Repository)) for how to create a custom repository)

The following example does not work to categorize the item. It is a good example to show how a reference to another profile could be used but the wiki page handler (when last updated) still does not have categorization. To categorize objects, use the category handler.
{CODE(caption=>SampleDataProfile,wrap=>1)}
objects:
 -
  type: wiki_page
  ref: sample_page
  data:
   name: Sample Profile
   category: $CategoryTreeProfile:app_category
   content: |
    ...
{CODE}

References don't have to be in a logical place. Profiles are a big data structure. Each part may or may not be interpreted depending on what features are supported. To have profiles that call other profiles see ((Profile dependencies)).


!! Alternative Syntax

In larger portions of text, references can be be made using ''$profileobject:example.com:SampleProfile:object_name$''. The same reduced patterns can be used.

This syntax is especially useful if a value in the object is fetched from a remote location using the ''wikicontent:'' handler. See ((Wiki Handler)) for an example.