Nonterminal complexity of tree controlled grammars

This paper studies the nonterminal complexity of tree controlled grammars. It is proved that the number of nonterminals in tree controlled grammars without erasing rules leads to an infinite hierarchy of families of tree controlled languages, while every recursively enumerable language can be generated by a tree controlled grammar with erasing rules and at most nine nonterminals

Strictly Locally Testable and Resources Restricted Control Languages in Tree-Controlled Grammars

Tree-controlled grammars are context-free grammars where the derivation process is controlled in such a way that every word on a level of the derivation tree must belong to a certain control language. We investigate the generative capacity of such tree-controlled grammars where the control languages are special regular sets, especially strictly locally testable languages or languages restricted by resources of the generation (number of non-terminal symbols or production rules) or acceptance (number of states). Furthermore, the set theoretic inclusion relations of these subregular language families themselves are studied.Comment: In Proceedings AFL 2023, arXiv:2309.0112

Parallel Syntax Analysis

Diplomová práce se zabývá moderními metodami pro popis jazyků. Představuje několik řízených gramatik, přičemž podrobněji se věnuje stromem řízené gramatice. Je založena na relativně nové technice syntaktické analýzy, která využívá právě stromem řízené gramatiky. V textu je blíže popsán postup této analýzy a následně návrh, jak jí zpracovat paralelně. Daný návrh se nám podařilo implementovat a syntaktickou analýzu tím posílit z hlediska rychlosti, čímž jsme dosáhli hlavního cíle této práce.This thesis focuses on modern methods of language description. It introduces several controlled grammars, describing in detail the tree controlled grammar. The thesis is based on relatively new technique of syntax analysis using tree controlled grammars. The process of this analysis is described in detail, followed by a design of parallel-processing of this analysis. We managed to succesfully implement this design, speed up the syntax analysis and therefore achieve the main goal of the thesis.

Demonstration of Tree Controlled Grammars Properties

Stromové gramatiky jsou gramatiky řízené prostřednictvím omezení kladených na jejich derivační stromy. Jedná se o jednoduché a přirozené rozšíření bezkontextových gramatik. Existuje několik typů kontroly derivačního stromu, v této práci jsou zmíněny dva principy: horizontální a vertikální kontrola. Součástí této práce je také aplikace pro demonstraci vlastností stromových gramatik, implementovaná v jazyce Python.Tree controlled grammars are grammars regulated by restriction placed on its derivation trees. It is simple and natural extension of context-free grammars. There are several types of derivation tree control, two principles are mentioned in this work: horizontal and vertical control. Application demonstrating tree controlled grammars properties, implemented in Python programming language, is also part of this work.

Tree transducers, L systems, and two-way machines

A relationship between parallel rewriting systems and two-way machines is investigated. Restrictions on the “copying power” of these devices endow them with rich structuring and give insight into the issues of determinism, parallelism, and copying. Among the parallel rewriting systems considered are the top-down tree transducer; the generalized syntax-directed translation scheme and the ETOL system, and among the two-way machines are the tree-walking automaton, the two-way finite-state transducer, and (generalizations of) the one-way checking stack automaton. The. relationship of these devices to macro grammars is also considered. An effort is made .to provide a systematic survey of a number of existing results