SDF is a formalism for the definition of syntax which is comparable to BNF in some respect, but has a wider scope in that it also covers the definition...

A syntax-directed translator first parses the source-language input into a parsetree, and then recursively converts the tree into a string in the target-language. We model this conversion by an extended treeto-string transducer that have multi-level trees on the source-side, which gives our system more expressive power and flexibility. We also define a direct probability model and use a linear-time dynamic programming algorithm to search for the best derivation. The model is then extended to the general log-linear framework in order to rescore with other features like n-gram language models. We devise a simple-yet-effective algorithm to generate non-duplicate k-best translations for n-gram rescoring. Initial experimental results on English-to-Chinese translation are presented. 1

Abstract. The n-pebble 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 n-pebble tree transducer can be realized by a composition of n + 1 0-pebble tree transducers. Next, the pebble tree transducer is compared with the macro tree transducer, a well-known model for syntax-directed semantics, with decidable type checking. The 0-pebble 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 0-pebble tree transducers. Together these simulations prove that (3) the composition closure of n-pebble tree transducers equals that of macro tree transducers (and that of 0-pebble tree transducers). Similar results hold in the nondeterministic case. Finally, (4) the output languages of deterministic n-pebble tree transducers form a hierarchy with respect to the number n of pebbles. 1

During the past few years, research into so-called

Every interactive system requires a presentation mechanism, to show the user the data it handles. Often, the relationship between the data and its presentation is complex; further, it is often mediated by astyle mechanism, allowing the user or a designer to describe how the data should be displayed. It is a standing engineering challenge to develop a presentation model that is exible, handling many kinds of data and layout; powerful, giving the user extensive control over appearance; and e cient enough for interactive work. In this dissertation, we propose a model of presentation by tree transformation. Because information often has a hierarchical logical structure, trees are widely used to represent documents and other data. The layout or presentation of a document is also often modeled as a computation over a tree. But these trees are not generally identical. In other words, presentation can be seen as a mapping between trees. Casting it as a formal tree transformation o ers both expressive, compact style speci cations and e cient implementation. We present a general framework for presentation by tree transformation. It has been implemented as part of Ensemble, a software development environment and multimedia document system

Context-Free Grammars (CFGs) are a simple and intuitively appealing formalism for the description of programming languages, but lack the computational power to describe many common language features. Over the past three decades, numerous extensions of the CFG model have been developed. Most of these extensions retain a CFG kernel, and augment it with a distinct facility with greater computational power. However, in all the most powerful CFG extensions, the clarity of the CFG kernel is undermined by the opacity of the more powerful extending facility. An intuitively appealing strategy for CFG extension is grammar adaptability, the principle that declarations in a program effectively modify the context-free grammar of the programming language. An adaptable grammar is equipped with some formal means for modifying its own CFG kernel. Most previous adaptable grammar formalisms have, unfortunately, failed to realize the potential clarity of this concept. In this thesis, a representative samp...

Abstract. The first main result is that if a macro tree translation is of linear size increase, i.e., if the size of every output tree is linearly bounded by the size of the corresponding input tree, then the translation is MSO definable (i.e., definable in monadic second-order logic). This gives a new characterization of the MSO definable tree translations in terms of macro tree transducers: they are exactly the macro tree translations of linear size increase. The second main result is that given a macro tree transducer, it can be decided whether or not its translation is MSO definable, and if it is then an equivalent MSO transducer can be constructed. Similar results hold for attribute grammars, which define a subclass of the macro tree translations.

The concept of macro tree transducer is a formal model for studying properties of syntax-- directed translations and of functional languages which are based on primitive recursion. In this paper, for output languages of producing and nondeleting macro tree transducers, we introduce and prove a pumping lemma. We apply this pumping lemma to gain two results: (1) there is no producing and nondeleting macro tree transducer which computes the set of all monadic trees with double exponential height as output and (2) there are hierarchies of producing and nondeleting macro tree transducers with respect to their number of functions. 1 Introduction Pumping lemmata are useful tools to prove that a given language L is not an element of a class L of formal languages, where L usually is defined by a class of grammars or translation schemes. Pumping lemmata have been investigated for different kinds of languages, for example string languages, tree languages, and graph languages. In this introduct...

This paper presents an algorithm that does this in two ways, one dealing with "right extension" and the other with "left recursion". A brief comparison with other parsing algorithms shows it to be related to the leftcorner parsing algorithm, but it is more flexible in the order that it permits phrases to be combined. It has many of the properties of the sentence analyzers of Marcus and Riesbeck, but is independent of the language theories on which those programs are based.

This paper investigates one problem related to the tension between building linguistically based parsers and building efficient ones. In particular, the issue of what is a linguistically motivated way of deriving a parser from principle-based theories of grammar is explored. It is argued that an efficient and faithful parser can be built by taking advantage of the way in which principles are stated. To support this claim, two features of an implemented parser are discussed. First, configurations and lexical information are precompiled separately into two tables (an table and a table of lexical co-occurrence) which gives rise to more compact data structures. Secondly, precomputation of syntactic features (O-roles, case, etc.) results in efficient computation of chains, because it reduces several problems of chain formation to a local computation, thus avoiding extensive search of the tree for an antecedent or extensive backtracking. It is also shown that this method of building long-distance dependencies can be computed incrementally