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Normal Form Algorithms for Extended ContextFree Grammars
 Theoretical Computer Science
, 2000
"... We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will p ..."
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We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of contextfree objects just as Grail does for regular objects. Our results generalize known complexity bounds for contextfree grammars but do so in nontrivial ways. Specifically, we introduce a new representation scheme for extended contextfree grammars (the symbolthreaded expression forest), a new normal form for these grammars (dot normal form) and new regular expression algorithms. 1 Introduction In the 1960's, extended contextfree grammars were introduced, based on BackusNaur form, as a useful abbreviatory notation that made contextfree grammars easier to write. More recently, the Standardized General Markup Language (SGML...
Instruction Computation in Subset Construction
 Automata Implementation
, 1996
"... Subset construction is the method of converting a nondeterministic finitestate machine into a deterministic one. The process of determinization is an important one in any implementation of finitestate machines since nondeterministic machines are often easier to describe than their deterministic eq ..."
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Subset construction is the method of converting a nondeterministic finitestate machine into a deterministic one. The process of determinization is an important one in any implementation of finitestate machines since nondeterministic machines are often easier to describe than their deterministic equivalents and the conversion of regular expressions to finitestate machines usually produces nondeterministic machines. We discuss one aspect of subset construction; namely, the computation of the instructions of the equivalent deterministic machine. Although the discussion is to some extent independent of any specific assumptions, we draw some conclusions within the context of INR and Grail, both packages for the manipulation of finitestate machines. The aim of the discussion is to present the problem and suggest some possible solutions; we do not intend to and cannot be definitive since much remains unknown. z This research was supported by grants from the Natural Sciences and Engineeri...
Extended ContextFree Grammars and Normal Form Algorithms
, 1998
"... We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will prov ..."
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Cited by 4 (2 self)
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We investigate the complexity of a variety of normalform transformations for extended contextfree grammars, where by extended we mean that the set of righthand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of contextfree objects just as Grail does for regular objects. Our results generalize known bounds for contextfree grammars but do so in nontrivial ways. Specifically, we introduce a new representation scheme for extended contextfree grammars (the symbolthreaded expression forest), a new normal form for these grammars (dot normal form) and new regular expression algorithms. 1 Introduction in the 1960's, extended contextfree grammars were introduced, using BackusNaur form, as a useful abbreviatory notation that made contextfree grammars easier to write. More recently, the Standardized General Markup Language (SGML) [13] used a similar ab...
Transition Diagram Systems and Normal Form Algorithms
, 1998
"... We investigate the complexity of a variety of normalform transformations for transition diagram systems, which are a parsing view of extended contextfree grammars. A transition diagram system is a finite collection of finitestate machines each of which is labeled with a unique nonterminal symbol. ..."
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Cited by 1 (1 self)
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We investigate the complexity of a variety of normalform transformations for transition diagram systems, which are a parsing view of extended contextfree grammars. A transition diagram system is a finite collection of finitestate machines each of which is labeled with a unique nonterminal symbol. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of contextfree objects just as Grail does for regular objects. 1 Introduction In the 1960's, extended contextfree grammars (as BackusNaur form) were introduced as a useful abbreviatory notation that made contextfree grammars easier to write. More recently, the Standardized General Markup Language (SGML) [17] used a similar abbreviatory notation to define extended contextfree grammars for documents. Currently, XML [4], which is a simplified version of SGML, is being promoted as the markup language for the web, instead of HTML (a specific grammar or DTD specified us...