WWW Programming using Computational Logic Systems (and the PiLLoW/CIAO Library)

Daniel Cabeza and Manuel Hermenegildo
{dcabeza,herme}@dia.fi.upm.es
CLIP Group
Computer Science Department
Technical University of Madrid (UPM), Spain

Abstract:

We discuss from a practical point of view a number of issues involved in writing Internet and WWW applications using LP/CLP systems. We describe PiLLoW, a public-domain Internet and WWW programming library for LP/CLP systems which we argue significantly simplifies the process of writing such applications. PiLLoW provides facilities for generating HTML structured documents, producing HTML forms, writing form handlers, accessing and parsing WWW documents, and accessing code posted at HTTP addresses. We also describe the architecture of some application classes, using a high-level model of client-server interaction, active modules. We then propose an architecture for automatic LP/CLP code downloading for local execution, using generic browsers. Finally, we also provide an overview of related work on the topic. The PiLLoW library has been developed in the context of the &-Prolog and CIAO systems, but it has been adapted to a number of popular LP/CLP systems, supporting most of its functionality.

Keywords: WWW, HTML, HTTP, Distributed Execution, (Constraint) Logic Programming

 
• Introduction
• Writing basic cgi-bin applications
• LP/CLP Scripts for CGI Applications
• Form Handling in HTTP
• Writing Form Handlers with PiLLoW
• Handling HTML as Prolog Terms
• Merging the Form Producer and the Handler
• Accessing WWW documents
• Providing Code Through the WWW
• A High-Level Model of Client-Server Interaction: Active Modules
• Automatic Code Downloading and Local Execution
• Related Work
• Conclusions and Future Work
• References