中文页面描述语言解释器CPDL2中的文字处理技术

页面描迷语言（PDL）已在电子出版等领城得到了广泛的应用, 本文阐述了中文页面描述语言解释器CPDL 2中文字处理的几项关健技术, 包括中西文字库的组织、高速还原、解释流程和hinting技术等     

中文页面描述语言解释器CPDL的设计与实现

页面描述语言（ＰＤＬ）已广泛应用于打印机、电子出版等领域，且已经诞生了国际标准（ＳＰＤＬ）。因此，开发中文页面描述语言解释器具有十分重要意义。本文介绍了中文页面描述语言解释器ＣＰＤＬ的特点、功能、数据结构、字库的组织和ＣＰＤＬ解释器流程。讨论了提高速度和压缩代码的方法，并给出了应用前景。     

页面描述语言PostScript字库机制的一个层次式实现模型

将国际流行的页面描述语言PostScript扩充以支持高质量的汉字页面的输出, 是近年来国内外对PostScript语言及其解释器研究的一个热点。本文提出了一个PostScript字库机制的层次式实现模型。该层次模型从语言的描述能力到字库解释器的实现, 充分体现了作者的两个目标：一是兼容和增强PostScript语言对页面上正文输出的灵活高效的描述能力, 并推广到大字符集, 多文种的应用场合；二是在解释器的字库技术上突破Adobe Type 1的局限, 使解释器能支持多种实用的字库技术, 特别是国内的多种曲线轮廓汉字库技术。本文同时提出了将字库技术从页面描述语言中独立出来的研究与开发方法。     

中文页面描述语言解释器中的复合字库技术

ＰｏｓｔＳｃｒｉｐｔ页面描述语言已在电子出版等领域得到了广泛应用。本文介绍了中文页面描述语言解释器中的复合字库技术，它能处理中、日、韩，并介绍了一个字库实例。     

CPDL解释器的实现模型

本文从ＣＰＤＬ解释器设计者的角度分析了页面描述语言的功能，并提出了ＣＰＤＬ解释器的一个通和层次模型，阐述了解释器各部份结构与其执行效率，还原速度和可移植性之间的联系。最后，文章还简单介绍了ＷｉｎＣＰＤＬ解释器的层次结构。     

中文页面描述语言解释器CPDL2中的文字处理技术

页面描述语言（ＰＤＬ）已在电子出版等领域得到了广泛的应用，本文阐述了中文页面描述语言解释器ＣＰＤＬ２中文字处理的几项关键技术，包括中西文字库的组织、高速还原、解释流程和ｈｉｎｔｉｎｇ技术等．     

中文页面描述语言文本管理器的设计与实现

文本管理器是用于提高中文页面描述语言解释器效率而引入的前处理系统，它包括资源管理、异常处理、ＥＰＳＦ管理和文本优化等功能模块．本文详细论述了文本管理器的设计思想与相应实现方法．     

中文页面描述语言解释器CPDL Level 2的设计与实现*

CPDL Level 2是一个面向彩色印刷的中文页面描述语言解释器，它与PostScriptLevel 2兼容．本文介绍了CPDL Level 2的虚拟机模型、层次结构和执行流程，并讨论了它的运行环境和效率．     

Implementing a performant scheme interpreter for the web in asm.js

This paper presents the implementation of an efficient interpreter for a Scheme-like language using manually written asm.js code. The asm.js specification defines an optimizable subset of JavaScript that has already served well as a compilation target for web applications where performance is critical. However, its usage as a human-writable language that can be integrated into existing projects to improve performance has remained largely unexplored. We therefore apply this strategy to optimize the implementation of an interpreter. We also discuss the feasibility of this approach, as writing asm.js by hand is generally not its recommended use-case. We therefore present a macro system to solve the challenges we encounter. The resulting interpreter is compared to the original C implementation and its compiled equivalent in asm.js. This way, we evaluate whether manual integration with asm.js provides the necessary performance to bring larger applications and runtimes to the web. We also refactor our implementation to assess how more JavaScript code can cohabit with asm.js code, improving maintainability of the implementation while preserving near-native performance. In the case of our interpreter, this improved maintainability enables adding more complex optimizations. We investigate the addition of function inlining, for which we validate the performance gain.     

Implementation of an interpreter for abstract equations

This paper summarizes a project whose goal is the implementation of a useful interpreter for abstract equations that is absolutely faithful to the logical semantics of equations. The interpreter was first distributed to Berkeley UNIX VAX sites in May 1983. The main novelties of the interpreter are strict adherence to semantics based on logical consequences, ‘lazy’ (outermost) evaluation applied uniformly, an implementation based on table-driven pattern matching, with no run-time penalty for large sets of equations, and strict separation of syntactic and semantic processing, so that different syntaxes may be used for different problems.     

Converting interpreters into compilers

There is an effective and quite general method of manually deriving compilers from programming-language interpreters without dealing directly with machine language. The method is an implementation of the largely theoretical and under-appreciated concept of partial computation, but can be understood on its own terms. It involves the translation of a source program's intermediate form into the interpreter's implementation language. This paper shows how the method can be used to transform both a sample iterative interpreter and a sample recursive interpreter into compilers. The result can be a large gain in program execution speed. Other advantages of the method, including the ease and practicality of applying it, are discussed.     

基于OSA/Parlay的VoiceXML解释器实现研究

VoiceXML技术能有效结合通信网和Internet,为电话用户提供丰富的语音应用。本文提出一种基于OSA/ParlayAPI(开放式应用编程接口)的VoiceXML解释器的设计与实现方案,能有效屏蔽不同制式电信网络的异构性,具有很好的跨平台通用性。针对解释器中业务状态变化多和网络功能扩展的需要,以state模式优化设计,从而保持整体系统的稳定性和可扩充性。最后说明了实现情况,并以一个具体业务运行时的消息处理流程为例对解释器的具体工作机制进行了进一步说明。     

High-level management of computation history for the design and implementation of a prolog system

We present the implementation of a Prolog system composed of interpreter and compiler. The originality of our work consists in the adoption of a new framework to realize the main components of the system. The framework relies on new mechanisms, called sleepers. With their help we have developed a complete Prolog interpreter in which all the control activities, from backtracking up to last-call optimization, are performed by the sleeper mechanism. We have also produced a Prolog compiler by using a philosophy and tactics that are completely independent of hardware constraints; it exploits an incremental and abstract implementation technique, based on a delayed non-local execution protocol. Our approach to Prolog system implementation has been extremely useful both in terms of software design and overall performance.     

On the implementation of bytecode compression for interpreted languages

This paper describes a new method for code space optimization for interpreted languages called LZW‐CC . The method is based on a well‐known and widely used compression algorithm, LZW , which has been adapted to compress executable program code represented as bytecode. Frequently occurring sequences of bytecode instructions are replaced by shorter encodings for newly generated bytecode instructions. The interpreter for the compressed code is modified to recognize and execute those new instructions. When applied to systems where a copy of the interpreter is supplied with each user program, space is saved not only by compressing the program code but also by automatically removing the unused implementation code from the interpreter. The method's implementation within two compiler systems for the programming languages Haskell and Java is described and implementation issues of interest are presented, notably the recalculations of target jumps and the automated tailoring of the interpreter to program code. Applying LZW‐CC to nhc98 Haskell results in bytecode size reduction by up to 15.23% and executable size reduction by up to 11.9%. Java bytecode is reduced by up to 52%. The impact of compression on execution speed is also discussed; the typical speed penalty for Java programs is between 1.8 and 6.6%, while most compressed Haskell executables run faster than the original. Copyright © 2008 John Wiley & Sons, Ltd.     

Dalvik虚拟机在龙芯平台上的移植与实现

在分析Dalvik虚拟机的结构和运行机制的基础上,针对龙芯处理器平台,研究移植Dalvik虚拟机的关键技术,描述Dalvik解释器的执行流程与方法调用过程中解释器栈帧的作用,实现可以完整运行Android系统的龙芯Dalvik虚拟机。对移植后的Dalvik虚拟机进行性能分析,并给出后续优化方案。     

实时嵌入式软件测试脚本技术研究

根据当前软件测试脚本技术的发展，结合实时嵌入式软件的特点，提出了脚本化的实时嵌入式软件测试的实现机制，并分别针对嵌入式软件测试脚本语言的设计及其相应解释器的实现进行了阐述。     

嵌入式JavaScript对象实现技术研究

给出了自主设计和开发的嵌入式浏览器JLBmwser的JavaScript解释系统模块结构图，讨论了JavaScript解释系统中实现对象的几个关键技术。在传统算符优先归约算法的基础上，提出了扩展的、基于对象的算符优先算法。     

Perl后端到JVM的移植

描述了Perl解释器的框架,介绍其后端虚拟机（Perl VM)的工作机理,给出了PVM所用到的栈,数据类型以及操作码函数（PP Code)在Java中的设计和实现,并陈述了在此移植中的几个关键问题及其解决方法。