Interesting direct manipulation paper


The paper might be of 
interest for those of you who do direct manip interfaces, as its ideas are 
very visad-compatible.

Basically, expressions like "mouse_down AND some_value < 2" can trigger state 
changes inside an app-specific state transition diagram.

It employs a data-flow network, where "routes", that is, flows of variables 
thru the network, are activated and deactivated depending on the current 

A simple example: if the above expression yields true, a state change is 
triggered, that activates a data-flow route from the mouse-position to some 

I don't know if this is an old hat, but I think it's it very cool.