Results 1  10
of
56
Macro Tree Transducers, Attribute Grammars, and MSO Definable Tree Translations
 Inform. and Comput
, 1998
"... A characterization is given of the class of tree translations definable in monadic second order logic (MSO), in terms of macro tree transducers. The first main result is that the MSO definable tree translations are exactly those tree translations realized by macro tree transducers (MTTs) with reg ..."
Abstract

Cited by 58 (22 self)
 Add to MetaCart
A characterization is given of the class of tree translations definable in monadic second order logic (MSO), in terms of macro tree transducers. The first main result is that the MSO definable tree translations are exactly those tree translations realized by macro tree transducers (MTTs) with regular lookahead that are single use restricted. For this the single use restriction known from attribute grammars is generalized to MTTs. Since MTTs are closed under regular lookahead, this implies that every MSO definable tree translation can be realized by an MTT. The second main result is that the class of MSO definable tree translations can also be obtained by restricting MTTs with regular lookahead to be finite copying, i.e., to require that each input subtree is processed only a bounded number of times. The single use restriction is a rather strong, static restriction on the rules of an MTT, whereas the finite copying restriction is a more liberal, dynamic restriction on the ...
A comparison of pebble tree transducers with macro tree transducers
 Acta Informatica
, 2003
"... Abstract. The npebble tree transducer was recently proposed as a model for XML query languages. The four main results on deterministic transducers are: First, (1) the translation τ of an npebble tree transducer can be realized by a composition of n + 1 0pebble tree transducers. Next, the pebble t ..."
Abstract

Cited by 41 (10 self)
 Add to MetaCart
Abstract. The npebble tree transducer was recently proposed as a model for XML query languages. The four main results on deterministic transducers are: First, (1) the translation τ of an npebble tree transducer can be realized by a composition of n + 1 0pebble tree transducers. Next, the pebble tree transducer is compared with the macro tree transducer, a wellknown model for syntaxdirected semantics, with decidable type checking. The 0pebble tree transducer can be simulated by the macro tree transducer, which, by the first result, implies that (2) τ can be realized by an (n+1)fold composition of macro tree transducers. Conversely, every macro tree transducer can be simulated by a composition of 0pebble tree transducers. Together these simulations prove that (3) the composition closure of npebble tree transducers equals that of macro tree transducers (and that of 0pebble tree transducers). Similar results hold in the nondeterministic case. Finally, (4) the output languages of deterministic npebble tree transducers form a hierarchy with respect to the number n of pebbles. 1
Macro Forest Transducers
 Information Processing Letters
, 2004
"... Abstract Xml documents conceptually are not trees, but forests. Therefore, we extend the concept of macro tree transducers (mtt’s) to a transformation formalism of forests, macro forest transducers (mft’s). We show that mft’s form a strict superset of mtt’s operating on forests (represented as binar ..."
Abstract

Cited by 35 (2 self)
 Add to MetaCart
(Show Context)
Abstract Xml documents conceptually are not trees, but forests. Therefore, we extend the concept of macro tree transducers (mtt’s) to a transformation formalism of forests, macro forest transducers (mft’s). We show that mft’s form a strict superset of mtt’s operating on forests (represented as binary trees). On the other hand, the transformation of every mft can be simulated by the composition of two mtt’s. Although macro forest transducers are more powerful, the complexity of inverse type inference, i.e., computing the preimage of a recognizable language, is almost the same as for tree transducers.
Benefits of Tree Transducers for Optimizing Functional Programs
 In FST & TCS'98, Chennai, India, Proceedings, volume 1530 of LNCS
, 1998
"... We present a technique to prevent the construction of intermediate data structures in functional programs, which is based on results from the theory of tree transducers. We first decompose function definitions, which correspond to macro tree transducers, into smaller pieces. Under certain restrictio ..."
Abstract

Cited by 32 (6 self)
 Add to MetaCart
(Show Context)
We present a technique to prevent the construction of intermediate data structures in functional programs, which is based on results from the theory of tree transducers. We first decompose function definitions, which correspond to macro tree transducers, into smaller pieces. Under certain restrictions...
Symbolic Finite State Transducers: Algorithms and Applications
"... Finite automata and finite transducers are used in a wide range of applications in software engineering, from regular expressions to specification languages. We extend these classic objects with symbolic alphabets represented as parametric theories. Admitting potentially infinite alphabets makes thi ..."
Abstract

Cited by 25 (9 self)
 Add to MetaCart
(Show Context)
Finite automata and finite transducers are used in a wide range of applications in software engineering, from regular expressions to specification languages. We extend these classic objects with symbolic alphabets represented as parametric theories. Admitting potentially infinite alphabets makes this representation strictly more general and succinct than classical finite transducers and automata over strings. Despite this, the main operations, including composition, checking that a transducer is singlevalued, and equivalence checking for singlevalued symbolic finite transducers are effective given a decision procedure for the background theory. We provide novel algorithms for these operations and extendcompositiontosymbolic transducersaugmentedwith registers. Our base algorithms are unusual in that they are nonconstructive, therefore, we also supply a separate model generation algorithm that can quickly find counterexamples in the case two symbolic finite transducers are not equivalent. The algorithms give rise to a complete decidable algebra of symbolic transducers. Unlike previous work, we do not need any syntactic restriction of the formulas on the transitions, only a decision procedure. In practice we leverage recent advances in satisfiability modulo theory (SMT) solvers. We demonstrate our techniques on four case studies, covering a wide range of applications. Our techniques can synthesize string preimages in excess of 8,000 bytes in roughly a minute, and we find that our new encodings significantly outperform previous techniques in succinctness and speed of analysis.
Comparison of Deforestation Techniques for Functional Programs and for Tree Transducers
 In FLOPS'99
, 1999
"... We compare transformations for the elimination of intermediate results in firstorder functional programs. We choose the well known deforestation technique of Wadler and composition techniques from the theory of tree transducers, of which the implementation of functional programs yet does not ta ..."
Abstract

Cited by 20 (5 self)
 Add to MetaCart
(Show Context)
We compare transformations for the elimination of intermediate results in firstorder functional programs. We choose the well known deforestation technique of Wadler and composition techniques from the theory of tree transducers, of which the implementation of functional programs yet does not take advantage. We identify syntactic classes of function definitions for which both techniques deliver equally efficient results and for which one technique is more powerful than the other.
Composition of functions with accumulating parameters
 Journal of Functional Programming
, 2004
"... Many functional programs with accumulating parameters are contained in the class of macro tree transducers. We present a program transformation technique that can be used to solve the efficiency problems due to creation and consumption of intermediate data structures in compositions of such function ..."
Abstract

Cited by 20 (9 self)
 Add to MetaCart
(Show Context)
Many functional programs with accumulating parameters are contained in the class of macro tree transducers. We present a program transformation technique that can be used to solve the efficiency problems due to creation and consumption of intermediate data structures in compositions of such functions, where classical deforestation techniques fail. In order to do so, given two macro tree transducers under appropriate restrictions, we construct a single macro tree transducer that implements the composition of the two original ones. The imposed restrictions are more liberal than those in the literature on macro tree transducer composition, thus generalising previous results.
A Learning Algorithm for TopDown XML Transformations
 PODS'10
, 2010
"... A generalization from string to trees and from languages to translations is given of the classical result that any regular language can be learned from examples: it is shown that for any deterministic topdown tree transformation there exists a sample set of polynomial size (with respect to the mini ..."
Abstract

Cited by 20 (5 self)
 Add to MetaCart
(Show Context)
A generalization from string to trees and from languages to translations is given of the classical result that any regular language can be learned from examples: it is shown that for any deterministic topdown tree transformation there exists a sample set of polynomial size (with respect to the minimal transducer) which allows to infer the translation. Until now, only for string transducers and for simple relabeling tree transducers, similar results had been known. Learning of deterministic topdown tree transducers (dtops) is far more involved because a dtop can copy, delete, and permute its input subtrees. Thus, complex dependencies of labeled input to output paths need to be maintained by the algorithm. First, a MyhillNerode theorem is presented for dtops, which is interesting on its own. This theorem is then used to construct a learning algorithm for dtops. Finally, it is shown how our result can be applied to xml transformations (e.g. xslt programs). For this, a new dtdbased encoding of unranked trees by ranked ones is presented. Over such encodings, dtops can realize many practically interesting xml transformations which cannot be realized on firstchild/nextsibling encodings.
Decidability of the Finiteness of Ranges of Tree Transductions
 Inform. and Comput
, 1996
"... . The finiteness of ranges of tree transductions is shown to be decidable for TBY + , the composition closure of macro tree transductions. Furthermore, TBY + definable sets and TBY + computable relations are considered, which are obtained by viewing a tree as an expression that denotes an elem ..."
Abstract

Cited by 18 (9 self)
 Add to MetaCart
. The finiteness of ranges of tree transductions is shown to be decidable for TBY + , the composition closure of macro tree transductions. Furthermore, TBY + definable sets and TBY + computable relations are considered, which are obtained by viewing a tree as an expression that denotes an element of a given algebra. A sufficient condition on the considered algebra is formulated under which the finiteness problem is decidable for TBY + definable sets and for the ranges of TBY + computable relations. The obtained result applies in particular to the class of string languages that can be defined by TBY + transductions via the yield mapping. This is a large class which is proved to form a substitutionclosed full AFL. 1 Introduction The finiteness problem is one of the classical decidability problems in formal language theory. For a given language of interest, one usually does not wish to know whether that language is finite (because it usually is not), but rather whether the l...
Deciding Equivalence of TopDown XML Transformations in Polynomial Time
"... Many useful XML transformations can be formulated through deterministic topdown tree transducers. A canonical form for such transducers is presented which allows to decide equivalence of their induced transformations in polynomial time. If the transducer is total, the canonical form can be obtaine ..."
Abstract

Cited by 17 (4 self)
 Add to MetaCart
Many useful XML transformations can be formulated through deterministic topdown tree transducers. A canonical form for such transducers is presented which allows to decide equivalence of their induced transformations in polynomial time. If the transducer is total, the canonical form can be obtained in polynomial time as well.