摘要:

AbstractA variant of the well‐known recursive descent parsing technique is developed, based on the assumption that each non‐terminal of the language is implemented through a separate module. The modularization principle requires that the recursive descent parser of one non‐terminal must be written knowing only the production rules of that non‐terminal, and not the other parts of the language. This leads to a parsing technique which is ‘lazy’ in the sense that part of the parser is constructed during parsing, according to the needs of a particular input text. It turns out that this technique can be implemented as efficiently as conventional recursive descent parsing, which is one of the fastest known parsing methods. The main benefit of the technique is that it allows a language to be implemented in small pieces which are easy to modify, replace

ISSN:0038-0644    

DOI:10.1002/spe.4380200802

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe concept of atomic actions has been a useful and powerful abstraction in designing concurrent and fault‐tolerant systems. Nested atomic actions are used in hierarchically structured systems where an atomic action may itself be composed of other atomic actions. This paper presents a semaphore‐based protocol for synchronizing a set of concurrently executing nested atomic actions. The approach followed consists of first designing a protocol for synchronizing non‐nested actions, and then extending it to the nested case. The paper also details the difficulties involved in integrating deadlock resolution algorithms into the synchronization protocol. Both deadlock‐prevention and deadlock‐detection schemes for handling deadlocks are

ISSN:0038-0644    

DOI:10.1002/spe.4380200803

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractWe describe our practical experience in the use of formal verification to obtain increased confidence in the design of safety‐critical systems. The experiment involved demonstrating the consistency of the design specifications of SIFT, a software‐implemented fault‐tolerant operating system for aircraft flight control. Specifications were written at successive levels of abstraction from the most abstract requirements definition down to the detailed level of program code. Consistency of the successive levels of specification was demonstrated using the enhanced HDM verification system. Formal verification is currently feasible only for carefully simplified systems, but there appears to be no alternative method that can meet the extreme safety requirements for safety‐critical

ISSN:0038-0644    

DOI:10.1002/spe.4380200804

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA method for extending the LR parsing method to enable it to deal with context‐free grammars containing embedded restrictions is presented. Such restrictions are usually dealt with in LR‐based parsers by executing semantic code outside the context of the LR method. By including such restrictions within the LR method itself, potential shift‐reduce and reduce‐reduce conflicts can be resolved and provide greater control over the language accepted. The proposed method can be incorporated easily into existing LR‐based parser‐generat

ISSN:0038-0644    

DOI:10.1002/spe.4380200805

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractTechniques for optimization on a parallel architecture are presented, and are applied to a proprietary simulation code. Software tools available on most UNIX systems are used extensively in these techniques. Methods for determining where to partition an application for maximum benefit from parallelism are discussed, along with a way for determining what portion of the application has been parallelized. Finally, an algorithm is given which can be used to predict the effect on computation time of adding additional processors.

ISSN:0038-0644    

DOI:10.1002/spe.4380200806

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper describes software that allows the user to edit the output of several common software tools and to cause the changes to be written back to the input files. For example, it is possible to edit the output of a spelling checker and have the changes propagated back to the source files. This technique makes some corrections simpler and more direct. A trial implementation is embedded in Emacs.

ISSN:0038-0644    

DOI:10.1002/spe.4380200807

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380200801

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY