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Syntax Diagram
Syntax diagrams (or railroad diagrams) are a way to represent a context-free grammar. They represent a graphical alternative to Backus–Naur form, EBNF, Augmented Backus–Naur form, and other text-based grammars as metalanguages. Early books using syntax diagrams include the "Pascal User Manual" written by Niklaus Wirth (diagrams start at page 47) and the Burroughs CANDE Manual. In the compilation field, textual representations like BNF or its variants are usually preferred. BNF is text-based, and used by compiler writers and parser generators. Railroad diagrams are visual, and may be more readily understood by laypeople, sometimes incorporated into graphic design. The canonical source defining the JSON data interchange format provides yet another example of a popular modern usage of these diagrams. Principle of syntax diagrams The representation of a grammar is a set of syntax diagrams. Each diagram defines a "nonterminal" stage in a process. There is a main diagram whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context-free Grammar
In formal language theory, a context-free grammar (CFG) is a formal grammar whose production rules are of the form :A\ \to\ \alpha with A a ''single'' nonterminal symbol, and \alpha a string of terminals and/or nonterminals (\alpha can be empty). A formal grammar is "context-free" if its production rules can be applied regardless of the context of a nonterminal. No matter which symbols surround it, the single nonterminal on the left hand side can always be replaced by the right hand side. This is what distinguishes it from a context-sensitive grammar. A formal grammar is essentially a set of production rules that describe all possible strings in a given formal language. Production rules are simple replacements. For example, the first rule in the picture, :\langle\text\rangle \to \langle\text\rangle = \langle\text\rangle ; replaces \langle\text\rangle with \langle\text\rangle = \langle\text\rangle ;. There can be multiple replacement rules for a given nonterminal symbol. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backus–Naur Form
In computer science, Backus–Naur form () or Backus normal form (BNF) is a metasyntax notation for context-free grammars, often used to describe the syntax of languages used in computing, such as computer programming languages, document formats, instruction sets and communication protocols. It is applied wherever exact descriptions of languages are needed: for instance, in official language specifications, in manuals, and in textbooks on programming language theory. Many extensions and variants of the original Backus–Naur notation are used; some are exactly defined, including extended Backus–Naur form (EBNF) and augmented Backus–Naur form (ABNF). Overview A BNF specification is a set of derivation rules, written as ::= __expression__ where: * is a ''nonterminal'' (variable) and the __expression__ consists of one or more sequences of either terminal or nonterminal symbols; * means that the symbol on the left must be replaced with the expression on the right. * mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Augmented Backus–Naur Form
In computer science, augmented Backus–Naur form (ABNF) is a metalanguage based on Backus–Naur form (BNF), but consisting of its own syntax and derivation rules. The motive principle for ABNF is to describe a formal system of a language to be used as a bidirectional communications protocol. It is defined b''Internet Standard 68''("STD 68", type case sic), which is , and it often serves as the definition language for IETF communication protocols. supersedes . updates it, adding a syntax for specifying case-sensitive string literals. Overview An ABNF specification is a set of derivation rules, written as rule = definition ; comment CR LF where rule is a case-insensitive nonterminal, the definition consists of sequences of symbols that define the rule, a comment for documentation, and ending with a carriage return and line feed. Rule names are case-insensitive: , , , and all refer to the same rule. Rule names consist of a letter followed by letters, numbers, and hyph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalanguages
In logic and linguistics, a metalanguage is a language used to describe another language, often called the ''object language''. Expressions in a metalanguage are often distinguished from those in the object language by the use of italics, quotation marks, or writing on a separate line. The structure of sentences and phrases in a metalanguage can be described by a metasyntax. Types There are a variety of recognized metalanguages, including ''embedded'', ''ordered'', and ''nested'' (or ''hierarchical'') metalanguages. Embedded An embedded metalanguage is a language formally, naturally and firmly fixed in an object language. This idea is found in Douglas Hofstadter's book, '' Gödel, Escher, Bach'', in a discussion of the relationship between formal languages and number theory: "... it is in the nature of any formalization of number theory that its metalanguage is embedded within it." It occurs in natural, or informal, languages, as well—such as in English, where words ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niklaus Wirth
Niklaus Emil Wirth (born 15 February 1934) is a Swiss computer scientist. He has designed several programming languages, including Pascal (programming language), Pascal, and pioneered several classic topics in software engineering. In 1984, he won the Turing Award, generally recognized as the highest distinction in computer science, for developing a sequence of innovative computer languages. Biography Wirth was born in Winterthur, Switzerland, in 1934. In 1959, he earned a Bachelor of Science (B.S.) degree in electronic engineering from the Swiss Federal Institute of Technology Zürich (ETH Zürich). In 1960, he earned a Master of Science (MSc) from Université Laval, Canada. Then in 1963, he was awarded a PhD in Electrical Engineering and Computer Science (EECS) from the University of California, Berkeley, supervised by the computer design pioneer Harry Huskey. From 1963 to 1967, he served as assistant professor of computer science at Stanford University and again at the Univer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CANDE
{{disambiguation, geo ...
Cande may refer to: * Candé, a commune in western France * Čande, a village in Bosnia and Herzegovina * CANDE, a command-line shell * Candé, a surname: ** Baciro Candé, Guinea-Bissauan footballer ** Braima Candé, Portuguese footballer ** Mamadu Candé, Guinea-Bissauan footballer * Candel Astra, also known as ''cande'', an Uruguayan brand of candy See also * Candé-sur-Beuvron, a commune in the Loir-et-Cher, central France * Candes-Saint-Martin, a commune in the Indre-et-Loire, central France * Château de Candé, a castle in the Indre-et-Loire * Emmanuel Candès (born 1970), mathematician * Kande (other) * Candy (other) * Candi (other) Candi may refer to: * Candi of Indonesia, an Indonesian word for ''stupa'' (Buddhist temple, also used for Hindu temples in Indonesia) * Candi, Sidoarjo, a subdistrict of Sidoarjo, East Java, Indonesia * Candi & The Backbeat, a Canadian dance band, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JSON
JSON (JavaScript Object Notation, pronounced ; also ) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute–value pairs and arrays (or other serializable values). It is a common data format with diverse uses in electronic data interchange, including that of web applications with servers. JSON is a language-independent data format. It was derived from JavaScript, but many modern programming languages include code to generate and parse JSON-format data. JSON filenames use the extension .json. Any valid JSON file is a valid JavaScript (.js) file, even though it makes no changes to a web page on its own. Douglas Crockford originally specified the JSON format in the early 2000s. He and Chip Morningstar sent the first JSON message in April 2001. Naming and pronunciation The 2017 international standard (ECMA-404 and ISO/IEC 21778:2017) specifies "Pronounced , as in 'Jason and The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Exchange
Data exchange is the process of taking data structured under a ''source'' schema and transforming it into a ''target'' schema, so that the target data is an accurate representation of the source data.A. Doan, A. Halevy, and Z. Ives.Principles of data integration, Morgan Kaufmann,s 2012 pp. 276 Data exchange allows data to be shared between different computer programs. It is similar to the related concept of data integration except that data is actually restructured (with possible loss of content) in data exchange. There may be no way to transform an instance given all of the constraints. Conversely, there may be numerous ways to transform the instance (possibly infinitely many), in which case a "best" choice of solutions has to be identified and justified. Single-domain data exchange In some domains, a few dozen different source and target schema (proprietary data formats) may exist. An "exchange" or "interchange format" is often developed for a single domain, and then necessar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red (programming Language)
Red is a programming language designed to overcome the limitations of the programming language Rebol. Red was introduced in 2011 by Nenad Rakočević, and is both an imperative and functional programming language. Its syntax and general usage overlaps that of the interpreted Rebol language. The implementation choices of Red intend to create a full stack programming language: Red can be used for extremely high-level programming (DSLs and GUIs) as well as low-level programming (operating systems and device drivers). Key to the approach is that the language has two parts: ''Red/System'' and ''Red''. * ''Red/System'' is similar to C, but packaged into a Rebol lexical structure for example, one would write instead of . * ''Red'' is a homoiconic language capable of meta-programming, with Rebol-like semantics. Red's runtime library is written in Red/System, and uses a hybrid approach: it compiles what it can deduce statically and uses an embedded interpreter otherwise. The project ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalanguage
In logic and linguistics, a metalanguage is a language used to describe another language, often called the ''object language''. Expressions in a metalanguage are often distinguished from those in the object language by the use of italics, quotation marks, or writing on a separate line. The structure of sentences and phrases in a metalanguage can be described by a metasyntax. Types There are a variety of recognized metalanguages, including ''embedded'', ''ordered'', and ''nested'' (or ''hierarchical'') metalanguages. Embedded An embedded metalanguage is a language formally, naturally and firmly fixed in an object language. This idea is found in Douglas Hofstadter's book, '' Gödel, Escher, Bach'', in a discussion of the relationship between formal languages and number theory: "... it is in the nature of any formalization of number theory that its metalanguage is embedded within it." It occurs in natural, or informal, languages, as well—such as in English, where words ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
