摘要:

AbstractThe UNIX operating system enjoys an ever increasing popularity throughout the computing community; there will be 1.4 million UNIX licences distributed by 1985, rising at a rate of about 400,000 per annum.With universal acceptance of a system comes a dangerously high degree of inertia. Consider the analogous area of programming languages, where there has been great resistance to change, despite major advancements.This paper presents a critique of UNIX, based on three areas which we consider to be of vital importance to future operating systems. These areas are operating system structures and design, programming support environments and distributed computing.The criticisms presented are in no way intended to discredit UNIX. UNIX compares favourably with most of the present generation of operating systems. The intention is to highlight deficiencies in the state of the art in operating system design.

ISSN:0038-0644    

DOI:10.1002/spe.4380151202

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractCertain ambiguities in the definition of Pascal imperil the portability of Pascal programs. Specifications and an implementation of alternative interpretations are presented. Context‐free grammars augmented with guarded commands are demonstrated as a notation for specifying the static context‐sensitive constraints of programming languages.Most of the advantages of context‐free grammars are preserved and yet the potential range of the syntactic definition component has been extended to encompass all static constraints. Context‐sensitive syntax typically tends to either clutter the semantic definition component or (as with type equivalence in Pascal) result in undesirable implementor‐dependent decisions.An implementation of a CFG‐based parser that automatically checks for the defined context‐sensitive constraints is also described. In addition stepwise abstraction is introduced as a practical technique for communicating formal programming languag

ISSN:0038-0644    

DOI:10.1002/spe.4380151203

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractA method to develop cross‐assemblers is explained by describing the XMETA system, where the advantages given by the semantic power of meta‐assemblies have been combined with the clarity of modern high level languages, such as Pascal, in defining assembly semantics. XMETA accepts a superset of the IEEE‐P694 microprocessor assembly language standard syntax: system structure is detailed and examples are provided to illustrate its use. Actual experiences are briefly summarized in the conclu

ISSN:0038-0644    

DOI:10.1002/spe.4380151204

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractThis 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 p

ISSN:0038-0644    

DOI:10.1002/spe.4380151205

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractCompiler writing tools, such as parser generators, are‐commonly used to build new operators. Nevertheless, constructing compilers by hand remains common. Such compilers are often built using recursive‐descent parsing for most of the language and operator‐precedence parsing for expressions. This paper describes a simple technique for parsing expressions using recursive descent that avoids the usual proliferation of procedures that occurs when recursive descent is used to parse expressions. By taking advantage of the similarity of the productions describing expressions in most languages, then+ 1 procedures usually required to parse expressions withnprecedence levels can be replaced with a table and two proce

ISSN:0038-0644    

DOI:10.1002/spe.4380151206

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380151201

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY