Top-down tree transducers with two-way tree walking look-ahead
نویسندگان
چکیده
منابع مشابه
Look-Ahead Removal for Top-Down Tree Transducers
Top-down tree transducers are a convenient formalism for describing tree transformations. They can be equipped with regular look-ahead, which allows them to inspect a subtree before processing it. In certain cases, such a look-ahead can be avoided and the transformation can be realized by a transducer without look-ahead. Removing the look-ahead from a transducer, if possible, is technically hig...
متن کاملHow to Remove the Look-Ahead of Top-Down Tree Transducers
For a top-down tree transducer with regular look-ahead we introduce the notion of difference bound, which is a number bounding the difference in output height for any two look-ahead states of the transducer. We present an algorithm that, for a given transducer with a known difference bound, decides whether it is equivalent to a transducer without regular look-ahead, and constructs such a transd...
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A composition procedure for linear and nondeleting extended top-down tree transducers is presented. It is demonstrated that the new procedure is more widely applicable than the existing methods. In general, the result of the composition is an extended top-down tree transducer that is no longer linear or nondeleting, but in a number of cases these properties can easily be recovered by a post-pro...
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We introduce a new syntax-directed translation device called top-down treeto-graph transducer. Such transducers are very similar to the usual top-down tree trans ducers except that the right-hand sides of their rules are hypergraphs rather than trees. Since we are aiming at a device which also allows to translate trees into objects ditTerent from graphs, we focus our attention on so-called tree...
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We investigate the typechecking problem for XML queries: statically verifying that every answer to a query conforms to a given output schema, for inputs satisfying a given input schema. As typechecking quickly turns undecidable for query languages capable of testing equality of data values, we return to the limited framework where we abstract XML documents as labeled ordered trees. We focus on ...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1992
ISSN: 0304-3975
DOI: 10.1016/0304-3975(92)90211-w