Distributed Language-based Environments

该项目继续了美国国家科学基金会先前资助的分布式语言环境研究。该项目的目标是开发变更传播的正式模型、基本算法和概念验证实现，该模型被建模为对定义集中式或分散式属性解析树的属性语法的并行和分布式增量评估，以响应树上的多个异步子树替换。在这个项目中，将研究这种变化传播的几个方面的算法，包括支持多个代理启动子树替换、维护底层数据结构和协调评估过程，并特别考虑属性评估和簿记成本之间的权衡。最初的应用是多用户分布式基于语言的编程环境，其中程序员使用由局域网连接的工作站并修改分散的属性分析树(程序)中的段(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).