摘要:

AbstractThe formatted syntax notation has been developed for the specification of formatted programming languages. This paper describes how a formatted syntax may be constructed for the purpose of prettyprinting an existing free‐format language. Those aspects of the system of particular relevance to free‐format languages are emphasized and their use explained. Also, a number of deficiencies in the defining metasyntax and formatting symbol repertoire are discussed. Practical enhancements and further areas of research are suggested. The programming language Modula‐2 is used for illustration, and a formatted syntax for it is

ISSN:0038-0644    

DOI:10.1002/spe.4380160702

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractMany current compilers produce in some situations wrong error messages that mislead the user and harm his confidence in the system. It is demonstrated that a reliable and efficient syntax error handling system may be produced automatically by a compiler generator from the BNF specification of the language, and without any effort by the language implementor. This result is achieved in three ways:(a)Some errors may not be diagnosed without knowledge of the intentions of the programmer. Some compilers employ a sophisticated analysis that attempts to capture these intentions, but which is not always successful. Such an elaborate analysis is not employed here, and instead a list of all the legal corrections is displayed, so that the programmer may readily select the right one.(b)The recovery symbols are selected by a ‘careful’ algorithm resulting in a high probability for correct error recovery.(c)The ‘honest’ error messages show also the parts of the code which could not be analysed correctly because of errors, and where more errors may exist.Efficiency is achieved by computing the recovery sets once and for all at compiler generation time, so that a fast error recovery at program compilation time is achieved. Experiments with erroneous programs suggest that the method compares well with the best compilers that we have seen, and is specially good at the avoidance of wrong error m

ISSN:0038-0644    

DOI:10.1002/spe.4380160703

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractMethods are given for finding a sequence of ‘add’, ‘subtract’ and ‘shift’ instructions to multiply the contents of a register by an integer constant. Each method generalizes the previous one and requires only a few intermediate or scratch registers. A variation of the last method is used in the PL.8 compiler and uses an unnoticeable amount of the overall compile time. Some statistics roughly indicating the effectiveness of the methods ar

ISSN:0038-0644    

DOI:10.1002/spe.4380160704

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractDbxtoolis a window‐ and mouse‐based debugger for C, Pascal and FORTRAN programs running on Sun workstations. Its use of the mouse as the primary input mechanism eliminates the need to type variables, line numbers, breakpoints and most commands. Its multiple windows provide several qualitatively different perspectives on the debugging problem. Compared to the Unix 4.2 BSDdbxfrom which it is derived, it has been extended with the abilities to debug multiple‐process programs, already‐running processes, and the Sun Operating System

ISSN:0038-0644    

DOI:10.1002/spe.4380160705

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractAn evolving network is subject to technological advances and increasing user demands through out its lifetime. Continuous monitoring is therefore required to understand its behaviour in the operational environment and to provide an aid to planning. A monitor tool has been developed to meet such requirements in a heavily used service network.A decentralized but integrated approach has been adopted. An active collection allows accumulated measurements to be retrieved. The measurements required are determined and the constraints imposed by existing mechanisms and the methods chosen are discussed.Flexible user facilities are available to allow selected measurements to be collected and displayed, and these are described.Daily sessions of network‐wide monitoring have been undertaken. The overhead incurred is quantified. The sessions revealed communications software errors and anomalous behaviour of a network node. Further analysis shows the symptoms of the latter, the result of a hardware fault.Enhancements which would increase the flexibility of the tool are also suggeste

ISSN:0038-0644    

DOI:10.1002/spe.4380160706

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380160701

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY