Question

Please go to TWikiAppPackageHowToDiscussion for continued discussion on this topic.

-- MattEngland - 11 Apr 2005

What is the difference between an Add-On and a Plugin? I see both things listed on Codev, and I as of yet fail to see their difference in concept, application, usage, meaning, etc.

My only potential speculation: "Add-On" was the old name for what is now known as "Plugin"? This is only speculation.

In the answer, can someone also explain the need/purpose for these 2 different mechanisms?

-- MattEngland - 09 Apr 2005

Environment

-- MattEngland - 09 Apr 2005

Answer

From the Plugins WebHome:

• "An add-on runs separately from the TWiki scripts, e.g. for data import, export to static HTML, etc."
• "A Plugin is loaded at run-time by the TWiki scripts on the server..."

The basic difference is that Plugins are integrated directly into TWiki's page rendering engine whereas add-ons are mostly separate applications that add some utility. Addons also include TWikiApplications that don't contain any code but only sets of TWiki topics that serve some purpose (such as my TopicClassificationAddOn). If you scan through the descriptions AddOnPackages and PluginPackages, I think this distinction will become clearer.

-- LynnwoodBrown - 09 Apr 2005

Lynnwood is right; though there is a further distinction, the Contrib. An Add-On may not use TWiki at all, a Plugin extends TWiki only through using the TWiki::Func plugins interface, and a Contrib extends the core TWiki functionality by tapping directly into the core code using unpublished APIs.

The terminology is loose, and has been widely abused.

-- CrawfordCurrie - 10 Apr 2005

All three enhancements are known as TWikiExtensions

-- FranzJosefSilli - 10 Apr 2005

It seems to me that these use for different designations (Add-On, Plugin, Contrib, Skins) for TWikiExtensions have most meaning for developers, less meaning for TWiki admins, and almost no meaning (in terms of distinguishing between the aforementioned designations as "extensions") for TWiki users.

Is this a fair assessment? (Since I'm a brand-new admin and have yet to make a TWiki extension, I may learn more about how this looks from an admin's perspective in the future.)

Also: would it make sense with the above terminology to call the "Plugins" web the "Extensions" web instead of the "Plugins" web? (Even though this may not be practical for historical purposes, and consistent links, etc.)

-- MattEngland - 10 Apr 2005

The Plugins web was originally for plugins. Then came along Skins and they needed a home... Despite proposals to alleivate, some insist CoolURIsDontChange so we apparently stuck with what I agree is an inappropriate label.

As for the difference between a plugin and a addon. I typically judge AddOns hacks that does not fit the architecture, whereas plugins are supposed to apply a modicum of conformity. (See RefactorPluginAPI and AnalysisOfPluginsAPIUsage). We ought herald Applications too but some felt these didn't deserve a web of their own; somehow they didn't even get a classification in the Plugins web.

As a guide: I install plugins but I seldom go near an addon.

-- MartinCleaver - 10 Apr 2005

Plugins have been a great driver for TWiki's popularity.

As Lynnwood mentioned, Add-ons can be addon utilities and TWikiApplications. It is a confusing mix.

I see TWikiApplications as a key to further accelerate the deployment of TWiki in our key markets. Applications need to be organized better, we currently have Sandbox sample applications, apps listed in TWikiApplications, apps packaged as AddOnPackages in Plugins web, and historically also as TWikiAddOnProducts in the Codev web. Lets follow-up in TWikiAppPackageHowToDiscussion how to address this.

-- PeterThoeny - 11 Apr 2005

I started TWikiAppPackageHowToDiscussion as a placeholder discussion topic.

-- MattEngland - 11 Apr 2005