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Scannerless Parser
In computer science, scannerless parsing (also called lexerless parsing) performs tokenization (breaking a stream of characters into words) and parsing (arranging the words into phrases) in a single step, rather than breaking it up into a pipeline of a lexer followed by a parser, executing concurrently. A language grammar is scannerless if it uses a single formalism to express both the lexical (word level) and phrase level structure of the language. Dividing processing into a lexer followed by a parser is more modular; scannerless parsing is primarily used when a clear lexer–parser distinction is unneeded or unwanted. Examples of when this is appropriate include TeX, most wiki grammars, makefiles, simple application-specific scripting languages, and Raku. Advantages * Only one metalanguage is needed * Non-regular lexical structure is handled easily * "Token classification" is unneeded which removes the need for design accommodations such as "the lexer hack" and language r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASF+SDF Meta Environment
ASF may refer to: Arts and entertainment * Alabama Shakespeare Festival, a drama festival * ''Asimov's Science Fiction'', a U.S.-based English-language science fiction magazine containing SF stories Science and technology Biological * African swine fever virus (ASFV), the causative agent of African swine fever (ASF) * Altered Schaedler flora, a standardized consortium of gastrointestinal microbial species * Serine/arginine-rich splicing factor 1, a protein also known as alternative splicing factor 1 (ASF) Computing * Advanced Synchronization Facility, a proposed extension to the x86 instruction set architecture * Advanced Systems Format (formerly "Advanced Streaming Format", .asf), a Microsoft streaming format * Alert Standard Format, a protocol for remote management and control of systems in OS-absent environments * Antispam, Anti Spam Filtering, software and hardware protection layers used to fight email spam * Apache Software Foundation, an umbrella non-profit organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context-free Language
In formal language theory, a context-free language (CFL) is a language generated by a context-free grammar (CFG). Context-free languages have many applications in programming languages, in particular, most arithmetic expressions are generated by context-free grammars. Background Context-free grammar Different context-free grammars can generate the same context-free language. Intrinsic properties of the language can be distinguished from extrinsic properties of a particular grammar by comparing multiple grammars that describe the language. Automata The set of all context-free languages is identical to the set of languages accepted by pushdown automata, which makes these languages amenable to parsing. Further, for a given CFG, there is a direct way to produce a pushdown automaton for the grammar (and thereby the corresponding language), though going the other way (producing a grammar given an automaton) is not as direct. Examples An example context-free language is L = \, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacompiler
In computer science, a compiler-compiler or compiler generator is a programming tool that creates a parser, interpreter, or compiler from some form of formal description of a programming language and machine. The most common type of compiler-compiler is more precisely called a parser generator. It only handles syntactic analysis. The input of a parser generator is a grammar file, typically written in Backus–Naur form (BNF) or extended Backus–Naur form (EBNF) that defines the syntax of a target programming language. The output is the source code of a parser for the programming language. The output of the (compiled) parser source code is a parser. It may be either standalone or embedded. This parser takes as an input the source code of the target programming language source and performs some action or outputs an abstract syntax tree (AST). Parser generators do not handle the semantics of the AST, or the generation of machine code for the target machine."A Syntax Directed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TREE-META
The TREE-META (or Tree Meta, TREEMETA) Translator Writing System is a compiler-compiler system for context-free languages originally developed in the 1960s. Parsing statements of the metalanguage resemble augmented Backus–Naur form with embedded tree-building directives. Unparsing rules include extensive tree-scanning and code-generation constructs. History TREE-META was instrumental in the development of the oN-Line System and was ported to many systems including the Univac 1108, GE 645, SDS-940, ICL 1906A, PERQ, and UCSD p-System. Example This is a complete example of a TREE-META program extracted (and untested) from the more complete (declarations, conditionals, and blocks) example in Appendix 6 of the ICL 1900 TREE-META manual. That document also has a definition of TREE-META in TREE-META in Appendix 3. This program is not just a recognizer, but also outputs the assembly language for the input. It demonstrates one of the key features of TREE-META, which is tree pattern mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
META II
META II is a domain-specific programming language for writing compilers. It was created in 1963–1964 by Dewey Val Schorre at UCLA. META II uses what Schorre called syntax equations. Its operation is simply explained as: Each ''syntax equation'' is translated into a recursive subroutine which tests the input string for a particular phrase structure, and deletes it if found. Meta II programs are compiled into an interpreted byte code language. VALGOL and SMALGOL compilers illustrating its capabilities were written in the META II language, VALGOL is a simple algebraic language designed for the purpose of illustrating META II. SMALGOL was a fairly large subset of ALGOL 60. Notation META II was first written in META I, a hand-compiled version of META II. The history is unclear as to whether META I was a full implementation of META II or a required subset of the META II language required to compile the full META II compiler. In its documentation, META II is described as resembling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raku Rules
Raku may refer to: * Lake Raku, an artificial lake in Tallinn, Estonia * Raku ware, a type of pottery used in the Japanese tea ceremony * Raku, Nepal, a village in the Karnali Zone * ''RAkU'' (ballet), a ballet by Yuri Possokhov * Raku (programming language), a computer language formerly known as Perl 6 See also * Horse hair raku Horse hair raku is a method of decorating pottery through the application of horsehair and other dry carbonaceous material to the heated ware. The burning carbonaceous material creates smoke patterns and carbon trails on the surface of the heated ..., a method of decorating pottery * Raku-Go, a form of Japanese verbal entertainment {{Disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boolean Grammar
Boolean grammars, introduced by , are a class of formal grammars studied in formal language theory. They extend the basic type of grammars, the context-free grammars, with conjunction and negation operations. Besides these explicit operations, Boolean grammars allow implicit disjunction represented by multiple rules for a single nonterminal symbol, which is the only logical connective expressible in context-free grammars. Conjunction and negation can be used, in particular, to specify intersection and complement of languages. An intermediate class of grammars known as conjunctive grammars allows conjunction and disjunction, but not negation. The rules of a Boolean grammar are of the form A \to \alpha_1 \And \ldots \And \alpha_m \And \lnot\beta_1 \And \ldots \And \lnot\beta_n where A is a nonterminal, m+n \ge 1 and \alpha_1, ..., \alpha_m, \beta_1, ..., \beta_n are strings formed of symbols in \Sigma and N. Informally, such a rule asserts that every string w over \Sigma that satis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scannerless Boolean Parser
{{Infobox Software , name = SBP , developer = Adam Megacz , latest release version = 1.0 , latest release date = 2009 , platform = Java Virtual Machine , genre = Parser generator , license = BSD license , website archived home page The Scannerless Boolean Parser is an open-source scannerless GLR parser generator for boolean grammars. It was implemented in the Java programming language and generates Java source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo .... SBP also integrates with Haskell via LambdaVM. External links SBP: the Scannerless Boolean ParserSBP LDTA'06 articleWIX - wiki markup parser in SBP Haskell Parser generators Free software programmed in Java (programming language) Software using the BSD license ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirit Parser Framework
The Spirit Parser Framework is an object oriented recursive descent parser generator framework implemented using template metaprogramming techniques. Expression templates allow users to approximate the syntax of extended Backus–Naur form (EBNF) completely in C++. Parser objects are composed through operator overloading and the result is a backtracking LL(∞) parser that is capable of parsing rather ambiguous grammars. Spirit can be used for both lexing and parsing, together or separately. This framework is part of the Boost libraries. Operators Because of limitations of the C++ language, the syntax of Spirit has been designed around the operator precedences of C++, while bearing resemblance to both EBNF and regular expressions A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLR Parser
A GLR parser (GLR standing for "Generalized LR", where L stands for "left-to-right" and R stands for "rightmost (derivation)") is an extension of an LR parser algorithm to handle non-deterministic and ambiguous grammars. The theoretical foundation was provided in a 1974 paper by Bernard Lang (along with other general Context-Free parsers such as GLL). It describes a systematic way to produce such algorithms, and provides uniform results regarding correctness proofs, complexity with respect to grammar classes, and optimization techniques. The first actual implementation of GLR was described in a 1984 paper by Masaru Tomita, it has also been referred to as a "parallel parser". Tomita presented five stages in his original work, though in practice it is the second stage that is recognized as the GLR parser. Though the algorithm has evolved since its original forms, the principles have remained intact. As shown by an earlier publication, Lang was primarily interested in more easily use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TXL (programming Language)
TXL may refer to: * TXL (programming language) * Berlin Tegel Airport, defunct German airport (by IATA code) * Fictional computer in the ''Today's Special ''Today's Special'' is a Canadian children's television program produced by Clive VanderBurgh at TVOntario, originally broadcasting 120 episodes from 1981 to 1987. Much of the series was set in a department store, based on Simpson's then-flags ...'' animated series {{Disambig fr:TXL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
