Provide a means to control the execution order between interdependent plugins

[JeremyRuston]

One approach is for systemConfig tiddlers to return a value. It is proposed that this value be interpreted as a hashmap of output parameters:

• callMeBack: set to true to have the systemConfig tiddler be reexecuted again at the end of the currently scheduled tiddlers. This is designed to allow systemConfig tiddlers to 'bail out' if they can't executed until some dependent systemConfig tiddler has executed. This feature needs to be coded carefully to avoid deadlocks and endless loops

For example, return {callMeBack: true};

[UdoBorkowski]

This ticket was also subject in  this discussion

[UdoBorkowski]

Patch to fix this ticket, using the "Requires" slice approach

[UdoBorkowski]

A different approach than originally suggested is used, refering to an explicit list of plugins specified in the "Requires" slice of the plugin.

A patch is attached.

Here a brief description:

By default plugins are loaded in the order they are stored in the TiddlyWiki. You may change this plugin load order through the "Requires" slice of the plugin tiddler. This slice lists all plugins to be loaded before "this" plugin is loaded. The Requires slice is typically given in the header part of the plugin tiddler. E.g.

/***
|''Name:''|PluginD|
|''Source:''|http://example.com/#PluginD|
|''Requires:''|http://example.com/#PluginC PluginE|
***/

The plugins may be specified by their Name or their Source, in the same syntax as tags are specified in the Tags list ("BracketedList?").

Loading plugins using the Requires slice is done on a "best attempt" base. I.e. no errors will be reported e.g. if a plugin specified does not exists or cyclics are defined. If a plugin really needs a certain plugin it must explicitly check this, e.g. with code like this at the beginning of the plugin:

if (!version.extensions.ForEachTiddlerPlugin || version.extensions.ForEachTiddlerPlugin.version < 2)
    throw new Error("Requires ForEachTiddlerPlugin Version 2.0 or better");

[JeremyRuston]

Fixed in changeset:1965 and changeset:1966