Extended regular expressions of arbitrary star degrees
نویسندگان
چکیده
منابع مشابه
On Extended Regular Expressions
In this paper we extend the work of Campeanu, Salomaa and Yu [1] on extended regular expressions featured in the Unix utility egrep and the popular scripting language Perl. We settle the open issue of closure under intersection and provide an improved pumping lemma that will show that a larger class of languages is not recognizable by extended regular expressions. We also investigate some quest...
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We concider an extened algebra of regular events (languages) with intersection besides the usual operations. This algebra has the structure of a distributive lattice with monotonic operations; the latter property is crucial for some applications. We give a new complete Horn equational axiomatiztion of the algebra and develop some termrewriting techniques for constructing logical inferences of v...
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Syntactic constraints in Koskenniemi's Finite-State Intersection Grammar (FSIG) are logically less complex than their formalism (Koskenniemi et al., 1992) would suggest: It turns out that although the constraints in Voutilainen's (1994) FSIG description of English make use of several extensions to regular expressions, the description as a whole reduces to a finite combination of union, compleme...
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Ordinary software engineers and programmers can easily understand regular patterns, as shown by the immense interest in and the success of scripting languages like Perl, based essentially on regular expression pattern matching. We believe that regular expressions provide an elegant and powerful specification language also for monitoring requirements, because an execution trace of a program is i...
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It is dicult to express the denition of the comments of C language in a regular expression. However, the denition can be expressed by a simple regular expression by introducing a special symbol, called the any-symbol, that represents any single character, or by introducing a kind of negation symbol into regular expressions. In general, the problem of string pattern matching can be expressed as ...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1992
ISSN: 0304-3975
DOI: 10.1016/0304-3975(92)90075-q