Distributed Language-based Environments

该项目延续了NSF先前资助的基于分布式语言环境的研究。这个项目的目标是开发一个正式的模型、底层算法和变更传播的概念验证实现，它被建模为一个属性语法的并行和分布式增量评估，定义集中或分散的属性解析树，以响应树上的多个异步子树替换。在这个项目中，将研究这种更改传播的几个方面的算法，包括支持启动子树替换的多个代理，维护底层数据结构，以及评估过程的协调，特别要考虑属性评估和记账成本之间的权衡。最初的应用是基于多用户分布式语言的编程环境，其中程序员使用由局域网连接的工作站，并在分散的属性解析树（程序）中修改段（模块）。

This project continues NSF previously funded research in Distributed Language-based Environments. The objective of this project is to develop a formal model, underlying algorithms and proof-of-concept implementation of change propagation, which is modelled as parallel and distributed incremental evaluation of an attribute grammar defining centralized or decentralized attributed parse trees in response to multiple asynchronous subtree replacements on a tree. In this project, algorithms for several aspects of such change propagation will be investigated, including support for multiple agents initiating subtree replacements, maintenance of underlying data structures, and coordination of evaluation processes, with particular consideration to tradeoffs between attribute evaluation and bookkeeping costs. The initial application is to multi-user distributed language-based programming environments, where programmers employ workstations connected by a local area network and modify segments (modules) in a decentralized attributed parse tree (program).