排序方式: 共有21条查询结果,搜索用时 171 毫秒
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上下文无关语言分析树的一种表示形式 总被引:5,自引:0,他引:5
介绍了上下文无关语言(CFL)的句子的一种分析树表示,它适用用于一类与以往不同的CFL的应用,即对分析树空间效率要求较高且不需标记分析树的应用,典型的就是把CFL的句子用作算法加工对象,这种表示比传统分析树不仅空间较小,而且进行结构匹配的快速快,还介绍了这种分析树表示的实现技术。 相似文献
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一个支持规约获取的形式规约语言 总被引:9,自引:0,他引:9
该文介绍了形式规约语言LFC设计的一些主要方面,并通过例子说明了LFC的一些特色。形式规约语言LFC是为支持软件形式规约的获取工作而开发的。该语言以一种新的递归函数,即定义在上下文无关语言上的递归函数为基础,以上下文无关语言为数据类型,在语言级支持规约获取。LFC语言已被用作形式规约获取系统SAQ的一部分。使用表明,LFC是一个能力强、易使用的语言,适合软件形式规约获取之用,并且适合其它一些用途。 相似文献
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董韫美 《计算机研究与发展》1977,(6)
§1.引言循环的效率如何,是决定一台计算机或一个语言使用效率的重要因素之一。本文建议一组指令,可用来组织含非常出口的非递归子程序和循环,以及无奇点的递归子程序。文中证明了相应程序结构的正确性,并给出一个存储分配算法。这组指令较某机现行方案为简,论证起来也简单得多。在§2中说明机器的结构和指令。§3描述循环的程序结构和给出正确性证明。§4描述子程序的结构。§5介绍 S 站存储分配算法。 相似文献
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本文介绍一个基于三阶Bezier曲线的字形转换系统SOCS(stroketooutlineconvertionsystem).该系统作为汉字字形设计系统CCDS(Chinesecharacterdesignsystem)的后端,把CCDS产生的多笔划曲线轮廓字形数据加工成整字曲线轮廓字形数据.其结果适于多种高精度输出,如Postscript印字机.SOCS系统具有一定的通用性,它不只限于接受CCDS的加工结果,还可以作为独立的系统使用. 相似文献
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Recursive functions of context free languages (Ⅰ)——The definitions of CFPRF and CFRF 总被引:1,自引:0,他引:1
董韫美 《中国科学F辑(英文版)》2002,(1)
It is intended to establish the recursive function theory on context free languages (CFLs). In this paper, the function class CFRF and its proper subclass CFPRF were defined on CFLs; it is quite straightforward to use them for describing non-numerical algorithms. In fact, they are respectively the partial recursive functions and primitive recursive functions of context free languages. The structure induction method for proving CFPRF function properties was presented. A method for CFL sentence enumeration was given, the minimization operator was defined. Based on CFL sentence enumeration, the minimization operator evaluation method was given. Finally, the design and implementation principles of executable specification languages with the CFRF as theoretical basis were discussed. 相似文献
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Recursive functions of context free languages (Ⅱ)——Validity of CFPRF and CFRF definitions 总被引:2,自引:0,他引:2
董韫美 《中国科学F辑(英文版)》2002,45(2)
In this paper we proved that the function class CFRF and its proper subclass CFPRF are respectively the partial recursive functions and primitive recursive functions of context free languages (CFLs). Also we discussed the relation between them and recursive functions defined on other domains . It is indicated that the functions of natural numbers and/or symbol strings (words) are functions of CFLs. Several frequently used primitive recursive functions on words were given, including logical connectives, conditional expressions. Also the powerful operators (bounded maximization and minimization operators) for constructing primitive recursive functions were defined. Two important nontrivial algorithms, the characteristic function of arbitrary CFL and the parse function of CFL sentences were constructed. Based on them, the method for extending or restricting function domain was described. 相似文献
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