PL／0语言编译机制实现研究

为了帮助加深对计算机语言编译技术的理解和应用,引述了PL／0语言的文法体系,简要介绍了PL／0语言编译程序的基本构成部分及其大体功能。通过跟踪PL／0语言编译程序对一段示例程序进行处理的内部过程,对构成语言编译技术的主要组成部分即词法分析、语法分析、中间代码生成、存储器分配、表格管理、错误处理等过程进行了重点分析,详细叙述了其工作原理与实现机制以及相互之间的关系。     

The programming language standards scene, ten years on Paper 7: PL/I

This paper, one of a simultaneously published set on ten years of activity in programming language standards, describes the developments in standardization of the Programming Language PL/I which have taken place since 1983.     

Taming the PL/I syntax

Ideally the syntactic part of a PL/I compiler would be generated directly from the semi-formal definition of ANSI Standard PL/I. A practical approach to this is described, using finite state machines and an LALR parser generator. The parser uses a method due to Aoe which avoids list searching. Adapted for this method the PL/I grammar has 841 states. The parse table generator exploits the freedom to renumber states in a way that improves on previous algorithms for compacting the tables. The parser tables occupy less than 4K bytes.     

Six PL/I compilers

This paper describes an experimental evaluation of the execution speed of object programs produced by six PL/I compilers. A set of 139 representative PL/I statements were compiled and executed under the PL/I Optimizing, PL/I(F), PL/C, PL/I Checkout, SP/k and PLUTO compilers. An analysis is made of the relative speed of the object code produced by each compiler and also of the relative execution speed of each statement.     

GKD-Base PL/SQL存储函数实现的关键技术研究

介绍具有自主知识产权的某安全数据库管理系统GKD-Base的PL/SQL引擎,基于该引擎研究GKD-Base存储函数机制实现的关键技术。设计了函数管理器和执行状态堆栈,通过语法树表示存储函数编译后生成的中间代码,并解决了中间代码的执行问题。最后实现了IN、OUT、INOUT三种参数模式函数的参数传递机制。     

Handling asynchronous interrupts in a PL/1-like language

A method of handling asynchronous interrupts, which are defined to be events, in a highlevel, block-structured language is described. The language facilities are based on PL/1 conditions. The functions of an interrupt handler and its relationship with the execution time support for the language are defined and discussed. The development of the facilities being presented is also described. Solutions to design problems and implemenation details are stated. The use and benefits of the mechanism are discussed.     

A high-level debugger for PL/I,Fortran and Basic

Dartmouth College has implemented a single debugger for several languages sharing a common runtime environment: PL/I, Basic and Fortran. The debugger is fairly powerful; users set breakpoints and traces which occur whenever the values of given variables change, or whenever certain relational expressions become true, for example. All debugging is carried on in a syntax similar to that of a high-level language. This debugger was implemented in about a month. It should be fairly easy to implement on most timesharing systems. This paper describes the debugger's user interface and gives a rough sketch of its implementation.     

Effects of structured programming on PL/I programmers

A PL/I system has been implemented which automatically collects and saves information on every program compiled and executed. This note describes some of the analysis that has been performed on approximately 9,000 of these collected programs.     

A numerical profile of commercial PL/I programs

A sample of 120 production PL/I programs from several commercial computing installations has been studied. Data about the programs in the sample have been extracted by a PL/I scanning program. The statistical results of the study are presented in this document The paper concentrates on statistical data and not on general conclusions. The data are only interpreted to the extent that it is not ill-defined and misleading. The data profile the use of basic PL/I elements and the structure of programs written in PL/I. The reader of this report will get a better understanding of how PL/I has been used in the commercial environment up to 1974.     

应用PL／SQL存储过程实现动态报表

该文对Oracle的动态网页技术进行了分析和比较,详细介绍了如何使用Oracle的存储过程实现数据的及时发布,并给出了实例。     

使用PL/SQL语言开发Web应用的框架研究

提出使用PL/SQL开发Web应用的框架结构,同时介绍一个用此框架开发的已实际使用的粒子:教务网上注册系统,来进一步说明此框架的使用方法.     

PL/SQL中的异常管理

在大型数据库应用程序的构建过程中,难免程序在运行时不会出错,然而,代码如何响应和处理这些错误往往决定着一个应用程序的成功与否.从异常类型、如何引发异常、如何自定义异常、如何处理异常4个方面来探究PL/SQL中的异常处理机制.     

Oracle WebSerVer4.o及PL/SQL的应用

主要介绍了Oracle8.0 .4forUnix数据库的强大的网上发布产品—OracleWebServer4.0的内部机制 ,以及利用OracleWebServer4.0的PL/SQL包自动生成动态网页的方法 ,并在结尾举了一个典型的PL/SQL存储过程例子     

Extending PL/I for structured programming

General principles of structured programming, and practical aspects of applying those principles within the programming language PL/I, are discussed. Suitable extensions (and contractions) of that language are suggested.     

Fooling the user of a programming language

Fooling the user' of a programming language by ‘natural’ constructions can cause completely unpredictable reliability defects in software systems. Numerous examples show the extent of the problem. Two methods of overcoming it are presented: simple languages devoid of user-fooling powers, and explication languages to accompany the more powerful languages.     

PL/SQL Developer日志生成插件的开发与应用

运用插件技术可以对支持插件的软件进行功能性的扩展。通过研究插件(Plug-in)的基本原理,运用Delphi开发工具、Windows编程技术、DLL的方式,设计实现了一种用于PL/SQLDeveloper数据维护时,进行日志生成的插件,对该软件的功能进行了很好的扩展。     

PL/SQL函数及其在财务系统中的应用

结合银行财务管理系统开发的具体实践,介绍了PL/SQL函数及其在数据库应用系统开发中的应用.     

Towards a language for concurrent processes

In this paper we shall discuss concurrency in programming languages, with a view towards designing a process-oriented language which, by its inherent parallelism, is well suited to exploit the forthcoming generation of distributed processor networks. We shall start by discussing the traditional approach towards managing concurrency, with ‘monitors’ co-ordinating the interactions of ‘processes’, and shall demonstrate that this approach actually degrades concurrency by imposing sequentiality during interactions because it is based on the premise of co-ordinating secure access to shared resources. As a tool for interprocess communication it is felt that the ‘monitor’ is too far removed from the abstract nature of the problem, and so, as a purely engineering solution, it imposes too broad and too prolonged an exclusion to be acceptable in general. Instead we turn to a simpler, and ultimately more powerful notion of ‘message passing’ between parallel processes. We shall show how, if the message system is polymorphic, any data value, however large it is, can pass freely between any pair of processes. By making the processes themselves values in the language we shall discover that message networks can come into being dynamically, and tailor themselves to their applications as and when necessary by ‘short-circuiting’ extensive communications paths. We shall also see how, if the message system is inherently asynchronous, the degree of the parallelism in a system can be enhanced, not degraded, as more and elaborate communications paths develop, the only sequentiality in the system as a whole being imposed by synchronizing processes, not the message passing system itself. After discussing the various built-in system facilities that permit processes to dynamically find out about and study one another, thus permitting processes to set up and thereafter supervise whole subsystems, we shall round off by discussing the advantages of introducing the machines themselves into the language, making it possible for processes to become aware of, and then ‘migrate’ within, the topological structure of a multi-processor distributed network, moving closer to their application, or just to a less-loaded processor, as the need arises. To conclude we shall contrast this new-style process-oriented language with various existing programming languages which have experimented with concurrency, either implicitly or explicitly, in order to see if, and if so how, this new style is any simpler and more powerful than its precursors.     

PL/M codes mixing on single-board systems

For 8-bit microprocessors, there is no immediate software solution to the problem raised by block-structured procedures, ROM implanted and called from a program located in a memory area. What happens with the debugging and evaluation of application software intended for a single-board system is that the modules have to be tested one by one through the target system before they are gradually implemented into ROM. The use of an incircuit emulator prevents this difficulty from occurring but, as most of the time only one emulator is available for a few teams, its use seems to be restricted to integration into the hardware.This paper describes a software interface which allows the ROM-implemented code and the RAM-implemented code to communicate. It is thus possible to allocate the code obtained using a high-level language at two noncontiguous locations, the first in ROM for the procedures already checked and the second in RAM for the procedures to be debugged. The use of a monitor allows the debugging of the critical parts and the evaluation of all the software before burning it permanently into ROM.     

一种PL/M语言到C语言自动翻译器的设计与实现

各种程序设计语言的相互翻译技术是一项非常有意义的研究工作。探讨了将在嵌入式系统中广泛使用的PL/M语言翻译成应用更加广泛的C语言的基本实现技术与设计方法,并给出了一个自动翻译器的具体实现。