Two-stage Programming via the Client-servlet-coprocess Interaction Model

This paper presents the client-servlet-coprocess interaction model, a new form of the client-server model. The client-servlet-coprocess model uses an HTTP Java servlet to specialize a servlet-enabled Web server to provide on-line client sessions with an interactive program run as a coprocess for the servlet. This model is designed for experimenting online with prototypical implementations of the interactive program and provides an enhanced support for research contacts via the WWW. A concrete example that uses this model to create Two-Stage Programming (2sp) online sessions is focussed. 2sp is a new, mixed-paradigm experimental coordination language for producing both reliable and eecient programs. The current prototypical implementation of 2sp is an interpreter running under SML of New Jersey (SML'97). The client-servlet-coprocess model enables time-eecient, easy-to-use, online sessions for experimenting with 2sp. In addition, it shows its suitability for interactively presenting functional programs on the Web.