Sophtalk tutorials
Abstract
This paper presents the Sophtalk system through two tutorials that describe salient features of the system and explore appropriate design methods. Sophtalk implements an event model of communication. System objects, called stnodes, emit messages when significant events occur, such as the termination of a computation, a request for a service from another object, error condition- s, etc. Messages circulate asynchronously in a network of stnodes. An stnode's type determines which messages it will receive, upon reception an action corresponding to the message and stnode instance is triggered. In the first tutorial, a small network in which a calculator - possibly in a seperate process - serves several clients, we introduce the essential Sophtalk functionalities. In the second tutorial a news network, we concentrat- e on design aspects and illustrate traps to be avoided.