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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. ... [...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 practical disciplines (including the design and implementation of hardware and software). Computer science is generally considered an area of 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 problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing security vulnerabilities. Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of repositories o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonterminal Symbol
In computer science, terminal and nonterminal symbols are the lexical elements used in specifying the production rules constituting a formal grammar. ''Terminal symbols'' are the elementary symbols of the language defined by a formal grammar. ''Nonterminal symbols'' (or ''syntactic variables'') are replaced by groups of terminal symbols according to the production rules. The terminals and nonterminals of a particular grammar are two disjoint sets. Terminal symbols Terminal symbols are literal symbols that may appear in the outputs of the production rules of a formal grammar and which cannot be changed using the rules of the grammar. Applying the rules recursively to a source string of symbols will usually terminate in a final output string consisting only of terminal symbols. Consider a grammar defined by two rules. Using pictoric marks interacting with each other: # The symbol ר can become ди # The symbol ר can become д Here д is a terminal symbol because no rule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rewrite Rule
In mathematics, computer science, and logic, rewriting covers a wide range of methods of replacing subterms of a formula with other terms. Such methods may be achieved by rewriting systems (also known as rewrite systems, rewrite engines, or reduction systems). In their most basic form, they consist of a set of objects, plus relations on how to transform those objects. Rewriting can be non-deterministic. One rule to rewrite a term could be applied in many different ways to that term, or more than one rule could be applicable. Rewriting systems then do not provide an algorithm for changing one term to another, but a set of possible rule applications. When combined with an appropriate algorithm, however, rewrite systems can be viewed as computer programs, and several theorem provers and declarative programming languages are based on term rewriting. Example cases Logic In logic, the procedure for obtaining the conjunctive normal form (CNF) of a formula can be implemented as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Numerals
Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, each letter with a fixed integer value, modern style uses only these seven: The use of Roman numerals continued long after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced by Arabic numerals; however, this process was gradual, and the use of Roman numerals persists in some applications to this day. One place they are often seen is on clock faces. For instance, on the clock of Big Ben (designed in 1852), the hours from 1 to 12 are written as: The notations and can be read as "one less than five" (4) and "one less than ten" (9), although there is a tradition favouring representation of "4" as "" on Roman numeral clocks. Other common uses include year numbers on monuments and buildings and co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Town
A town is a human settlement. Towns are generally larger than villages and smaller than cities, though the criteria to distinguish between them vary considerably in different parts of the world. Origin and use The word "town" shares an origin with the German word , the Dutch word , and the Old Norse . The original Proto-Germanic word, *''tūnan'', is thought to be an early borrowing from Proto-Celtic *''dūnom'' (cf. Old Irish , Welsh ). The original sense of the word in both Germanic and Celtic was that of a fortress or an enclosure. Cognates of ''town'' in many modern Germanic languages designate a fence or a hedge. In English and Dutch, the meaning of the word took on the sense of the space which these fences enclosed, and through which a track must run. In England, a town was a small community that could not afford or was not allowed to build walls or other larger fortifications, and built a palisade or stockade instead. In the Netherlands, this space was a garden, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apartment
An apartment (American English), or flat (British English, Indian English, South African English), is a self-contained housing unit (a type of residential real estate) that occupies part of a building, generally on a single story. There are many names for these overall buildings, see below. The housing tenure of apartments also varies considerably, from large-scale public housing, to owner occupancy within what is legally a condominium ( strata title or commonhold), to tenants renting from a private landlord (see leasehold estate). Terminology The term ''apartment'' is favored in North America (although in some cities ''flat'' is used for a unit which is part of a house containing two or three units, typically one to a floor). In the UK, the term ''apartment'' is more usual in professional real estate and architectural circles where otherwise the term ''flat'' is used commonly, but not exclusively, for an apartment on a single level (hence a 'flat' apartment). In some coun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Initial
In a written or published work, an initial capital, also referred to as a drop capital or simply an initial cap, initial, initcapital, initcap or init or a drop cap or drop, is a letter at the beginning of a word, a chapter, or a paragraph that is larger than the rest of the text. The word is derived from the Latin ''initialis'', which means ''standing at the beginning''. An initial is often several lines in height and in older books or manuscripts are known as "inhabited" initials. Certain important initials, such as the Beatus initial or "B" of '' Beatus vir...'' at the opening of Psalm 1 at the start of a vulgate Latin. These specific initials in an illuminated manuscript were also called initiums. In the present, the word "initial" commonly refers to the first letter of any word or name, the latter normally capitalized in English usage and is generally that of a first given name or a middle one or ones. History The classical tradition was slow to use capital letters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Name
First or 1st is the ordinal form of the number one (#1). First or 1st may also refer to: *World record, specifically the first instance of a particular achievement Arts and media Music * 1$T, American rapper, singer-songwriter, DJ, and record producer Albums * ''1st'' (album), a 1983 album by Streets * ''1st'' (Rasmus EP), a 1995 EP by The Rasmus, frequently identified as a single * ''1ST'', a 2021 album by SixTones * ''First'' (Baroness EP), an EP by Baroness * ''First'' (Ferlyn G EP), an EP by Ferlyn G * ''First'' (David Gates album), an album by David Gates * ''First'' (O'Bryan album), an album by O'Bryan * ''First'' (Raymond Lam album), an album by Raymond Lam * ''First'', an album by Denise Ho Songs * "First" (Cold War Kids song), a song by Cold War Kids * "First" (Lindsay Lohan song), a song by Lindsay Lohan * "First", a song by Everglow from '' Last Melody'' * "First", a song by Lauren Daigle * "First", a song by Niki & Gabi * "First", a song by Jonas Brot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recursion (computer Science)
In computer science, recursion is a method of solving a computational problem where the solution depends on solutions to smaller instances of the same problem. Recursion solves such recursive problems by using functions that call themselves from within their own code. The approach can be applied to many types of problems, and recursion is one of the central ideas of computer science. Most computer programming languages support recursion by allowing a function to call itself from within its own code. Some functional programming languages (for instance, Clojure) do not define any looping constructs but rely solely on recursion to repeatedly call code. It is proved in computability theory that these recursive-only languages are Turing complete; this means that they are as powerful (they can be used to solve the same problems) as imperative languages based on control structures such as and . Repeatedly calling a function from within itself may cause the call stack to have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
End-of-line
Newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a sequence of characters, is used to signify the end of a line of text and the start of a new one. History In the mid-1800s, long before the advent of teleprinters and teletype machines, Morse code operators or telegraphists invented and used Morse code prosigns to encode white space text formatting in formal written text messages. In particular the Morse prosign (mnemonic reak ext) represented by the concatenation of literal textual Morse codes "B" and "T" characters sent without the normal inter-character spacing is used in Morse code to encode and indicate a ''new line'' or ''new section'' in a formal text message. Later, in the age of modern teleprinters, standardized character set control codes were developed to aid in white spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suffix (name)
A name suffix, in the Western English-language naming tradition, follows a person's full name and provides additional information about the person. Post-nominal letters indicate that the individual holds a position, educational degree, accreditation, office, or honor (e.g. "PhD", "CCNA", "OBE"). Other examples include generational designations like "Sr." and "Jr." and "I", "II", "III", etc. Another used is Sñr (Spanish for Mr). Post-nominal letters Academic Academic suffixes indicate the degree earned at a college or university. These include bachelor's degrees (AB, BA, BA (Hons), BS, BE, BFA, BTech, LLB, BSc, etc.), master's degrees ( MA, MS, MFA, LLM, MLA, MBA, MSc., MEng etc.), professional doctorates ( JD, MD, DO, PharmD, DMin., etc.), and academic doctorates (PhD., EdD., DPhil, DBA., LLD, EngD, etc.) In the case of doctorates, normally either the prefix (e.g. "Dr" or "Atty") or the suffix (see examples above) is used, but not both. In the United States, the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Last Name
In some cultures, a surname, family name, or last name is the portion of one's personal name that indicates one's family, tribe or community. Practices vary by culture. The family name may be placed at either the start of a person's full name, as the forename, or at the end; the number of surnames given to an individual also varies. As the surname indicates genetic inheritance, all members of a family unit may have identical surnames or there may be variations; for example, a woman might marry and have a child, but later remarry and have another child by a different father, and as such both children could have different surnames. It is common to see two or more words in a surname, such as in compound surnames. Compound surnames can be composed of separate names, such as in traditional Spanish culture, they can be hyphenated together, or may contain prefixes. Using names has been documented in even the oldest historical records. Examples of surnames are documented in the 11th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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