Notes on "Eva: An Event Driven Framework For Building User Interfaces In Smalltalk", Jeff McAffer and Dave Thomas, November, 1987.
This is an interesting assessment of Smalltalk user interfaces in the mid-1980s. Beyond that assessment is the design for a new user interface framework for Smalltalk. The framework is compared to Sun's NeWS and suggests Eva is better than NeWS in some ways.
The main similarities of Eva and NeWS are:
- Event-based
- Multiple active views
- Lightweight processes
- Portable interpretive language
- Reactive interaction with distributed applications
The main differences attributed to Smalltalk are:
- Smalltalk development environment
- Richer class library
- Better runtime garbage collector
- Better runtime performance
The advantage of these are to support more complex application user interfaces, for example CAD applications.
A prototype of Eva was developed in their Smalltalk/v system which ran in 600k. That Smalltalk was not truly multi-processing. The ultimate target for Eva was their Actra implementation of Smalltalk with "actors" providing true multi-processing. Subsequent work on their SmallScript system implemented the Postscript imaging model.
