Features, Dependencies, and the UI

A few weeks back, we wrote about our thought process for building features, and how we wanted to make sure that the features achieved two goals:

• Be part of a fully functioning install profile that "just worked"
• Be as reusable as possible within VoiceBox variants, or within other sites.

As part of achieving these goals, we created an option within our install profile that allows a user to select the Full or the Minimal install. The full install runs through the complete install, and creates a fully functioning site.

The minimal install, however, runs through the install profile, and then allows the site builder to enable the selected features they want.

Features are modules; this allows us to set dependencies between features. However, as we built out features based on our site configuration, we realized that the User Interface elements created the largest set of dependencies - and this makes sense, because a good UI collects up the various sets of functionality and presents them to users in an intuitive, coherent way. To account for this, we split out our UI into separate features, so someone doing a minimal install can choose to use these defaults, or build their own UI.

A graph of the dependencies shows this better than words can explain it:

• Dependency tree of VoiceBox without any UI (click the image to see a full-size version):

  

• Dependency tree of VoiceBox with the UI features included (click the image to see a full-size version):

  

  The elements pictured in blue are the UI-related features; within the site, they expose functionality to end users - this is also known as "making things useful or usable."

  Within the features, UI elements create a higher level of interdependence.

We are running through the last few rounds of testing here, and barring any nasty last-minute surprises, we should have a release of VoiceBox by tomorrow. Our features server, which will be launched with the site, will allow people to get the entire install as a package, or the bundled features individually.