Departmental Papers (CIS)

Date of this Version

7-2012

Document Type

Conference Paper

Comments

From the 39th International Colloquium, ICALP 2012, Warwick, UK, July 9-13, 2012.

Abstract

Theory of tree transducers provides a foundation for understanding expressiveness and complexity of analysis problems for specification languages for transforming hierarchically structured data such as XML documents. We introduce streaming tree transducers as an analyzable, executable, and expressive model for transforming unranked ordered trees (and hedges) in a single pass. Given a linear encoding of the input tree, the transducer makes a single left-to-right pass through the input, and computes the output in linear time using a finite-state control, a visibly pushdown stack, and a finite number of variables that store output chunks that can be combined using the operations of string-concatenation and tree-insertion. We prove that the expressiveness of the model coincides with transductions definable using monadic second-order logic (MSO). Existing models of tree transducers either cannot implement all MSO-definable transformations, or require regular look ahead that prohibits single-pass implementation. We show a variety of analysis problems such as type-checking and checking functional equivalence are decidable for our model.

Subject Area

CPS Theory

Publication Source

Lecture Notes in Computer Science: Automata, Languages, and Programming

Volume

7392

Start Page

42

Last Page

53

DOI

10.1007/978-3-642-31585-5_8

Copyright/Permission Statement

The original publication is available at www.springerlink.com

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Date Posted: 18 July 2012