Apple’s Model-View-Controller is Seeheim

Just reading the iPhone Cocoa developer docs and its description of Model-View-Controller. However, if you look at the diagram rather than the model component directly notifying the view of changes as in classic MVC, in Cocoa the controller acts as mediator, more like the Dialogue component in the Seeheim architecture1 or the Control component in PAC.

MVC from Mac Cocoa development docs

The docs describing the Cocoa MVC design pattern in more detail in fact do a detailed comparison with the Smalltalk MVC, but do not refer to Seeheim or PAC, I guess because they are less well known now-a-days.  Only a few weeks ago when discussing architecture with my students, I described Seeheim as being more a conceptual architecture and not used in actual implementations now.  I will have to update my lectures – Seeheim lives!

  1. Shocked to find no real web documentation for Seeheim, not even on Wikipedia; looks like CS memory is short.  However, it is described in chapter 8 of the HCI book and in the chapter 8 slides[back]