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Two-level Grammar
In computer science, a Van Wijngaarden grammar (also vW-grammar or W-grammar) is a formalism for defining formal languages. The name derives from the formalism invented by Adriaan van Wijngaarden for the purpose of defining the ALGOL 68 programming language. The resulting specification remains its most notable application. Van Wijngaarden grammars address the problem that context-free grammars cannot express agreement or reference, where two different parts of the sentence must agree with each other in some way. For example, the sentence "The birds was eating" is not Standard English because it fails to agree on number. A context-free grammar would parse "The birds was eating" and "The birds were eating" and "The bird was eating" in the same way. However, context-free grammars have the benefit of simplicity whereas van Wijngaarden grammars are considered highly complex. Two levels W-grammars are two-level grammars: they are defined by a pair of grammars, that operate on differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). 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 preventing security vulnerabilities. Computer graphics (computer science), 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 re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turing Complete
Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher and theoretical biologist. He was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer. Turing is widely considered to be the father of theoretical computer science. Born in London, Turing was raised in southern England. He graduated from King's College, Cambridge, and in 1938, earned a doctorate degree from Princeton University. During World War II, Turing worked for the Government Code and Cypher School at Bletchley Park, Britain's codebreaking centre that produced Ultra intelligence. He led Hut 8, the section responsible for German naval cryptanalysis. Turing devised techniques for speeding the breaking of German ciphers, including improvements to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backus–Naur Form
In computer science, Backus–Naur form (BNF, pronounced ), also known as Backus normal form, is a notation system for defining the Syntax (programming languages), syntax of Programming language, programming languages and other Formal language, formal languages, developed by John Backus and Peter Naur. It is a metasyntax for Context-free grammar, context-free grammars, providing a precise way to outline the rules of a language's structure. It has been widely used in official specifications, manuals, and textbooks on programming language theory, as well as to describe Document format, document formats, Instruction set, instruction sets, and Communication protocol, communication protocols. Over time, variations such as extended Backus–Naur form (EBNF) and augmented Backus–Naur form (ABNF) have emerged, building on the original framework with added features. Structure BNF specifications outline how symbols are combined to form syntactically valid sequences. Each BNF consists of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALGOL 60
ALGOL 60 (short for ''Algorithmic Language 1960'') is a member of the ALGOL family of computer programming languages. It followed on from ALGOL 58 which had introduced code blocks and the begin and end pairs for delimiting them, representing a key advance in the rise of structured programming. ALGOL 60 was one of the first languages implementing function definitions (that could be invoked recursively). ALGOL 60 function definitions could be nested within one another (which was first introduced by any programming language), with lexical scope. It gave rise to many other languages, including CPL, PL/I, Simula, BCPL, B, Pascal, and C. Practically every computer of the era had a systems programming language based on ALGOL 60 concepts. Niklaus Wirth based his own ALGOL W on ALGOL 60 before moving to develop Pascal. Algol-W was intended to be the next generation ALGOL but the ALGOL 68 committee decided on a design that was more complex and advanced rather than a cleaned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pronoun
In linguistics and grammar, a pronoun (Interlinear gloss, glossed ) is a word or a group of words that one may substitute for a noun or noun phrase. Pronouns have traditionally been regarded as one of the part of speech, parts of speech, but some modern theorists would not consider them to form a single class, in view of the variety of functions they perform cross-linguistically. An example of a pronoun is "you", which can be either singular or plural. Sub-types include personal pronoun, personal and possessive pronouns, reflexive pronoun, reflexive and reciprocal pronoun, reciprocal pronouns, demonstrative pronouns, relative pronoun, relative and interrogative pronouns, and indefinite pronouns. The use of pronouns often involves anaphora (linguistics), anaphora, where the meaning of the pronoun is dependent on an antecedent (grammar), antecedent. For example, in the sentence ''That poor man looks as if he needs a new coat'', the meaning of the pronoun ''he'' is dependent on its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verb
A verb is a word that generally conveys an action (''bring'', ''read'', ''walk'', ''run'', ''learn''), an occurrence (''happen'', ''become''), or a state of being (''be'', ''exist'', ''stand''). In the usual description of English, the basic form, with or without the particle ''to'', is the infinitive. In many languages, verbs are inflected (modified in form) to encode tense, aspect, mood, and voice. A verb may also agree with the person, gender or number of some of its arguments, such as its subject, or object. In English, three tenses exist: present, to indicate that an action is being carried out; past, to indicate that an action has been done; and future, to indicate that an action will be done, expressed with the auxiliary verb ''will'' or ''shall''. For example: * Lucy ''will go'' to school. ''(action, future)'' * Barack Obama ''became'' the President of the United States in 2009. ''(occurrence, past)'' * Mike Trout ''is'' a center fielder. ''(state of bein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noun
In grammar, a noun is a word that represents a concrete or abstract thing, like living creatures, places, actions, qualities, states of existence, and ideas. A noun may serve as an Object (grammar), object or Subject (grammar), subject within a phrase, clause, or sentence.Example nouns for: * Living creatures (including people, alive, dead, or imaginary): ''mushrooms, dogs, Afro-Caribbeans, rosebushes, Mandela, bacteria, Klingons'', etc. * Physical objects: ''hammers, pencils, Earth, guitars, atoms, stones, boots, shadows'', etc. * Places: ''closets, temples, rivers, Antarctica, houses, Uluru, utopia'', etc. * Actions of individuals or groups: ''swimming, exercises, cough, explosions, flight, electrification, embezzlement'', etc. * Physical qualities: ''colors, lengths, porosity, weights, roundness, symmetry, solidity,'' etc. * Mental or bodily states: ''jealousy, sleep, joy, headache, confusion'', etc. In linguistics, nouns constitute a lexical category (part of speech) defined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verb Phrase
In linguistics, a verb phrase (VP) is a syntax, syntactic unit composed of a verb and its argument (linguistics), arguments except the subject (grammar), subject of an independent clause or coordinate clause. Thus, in the sentence ''A fat man quickly put the money into the box'', the words ''quickly put the money into the box'' constitute a verb phrase; it consists of the verb ''put'' and its arguments, but not the subject ''a fat man''. A verb phrase is similar to what is considered a ''predicate (grammar), predicate'' in traditional grammars. Verb phrases generally are divided among two types: finite, of which the Head (linguistics), head of the phrase is a finite verb; and nonfinite, where the head is a nonfinite verb, such as an infinitive, participle or gerund. Phrase structure grammars acknowledge both types, but dependency grammars treat the subject as just another verbal dependent, and they do not recognize the finite verbal phrase constituent (linguistics), constituent. Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noun Phrase
A noun phrase – or NP or nominal (phrase) – is a phrase that usually has a noun or pronoun as its head, and has the same grammatical functions as a noun. Noun phrases are very common cross-linguistically, and they may be the most frequently occurring phrase type. Noun phrases often function as verb subjects and objects, as predicative expressions, and as complements of prepositions. One NP can be embedded inside another NP; for instance, ''some of his constituents'' has as a constituent the shorter NP ''his constituents''. In some theories of grammar, noun phrases with determiners are analyzed as having the determiner as the head of the phrase, see for instance Chomsky (1995) and Hudson (1990) . Identification Some examples of noun phrases are underlined in the sentences below. The head noun appears in bold. ::This election-year's politics are annoying for many people. ::Almost every sentence contains at least one noun phrase. ::Current economic weakness may be a re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Part Of Speech
In grammar, a part of speech or part-of-speech ( abbreviated as POS or PoS, also known as word class or grammatical category) is a category of words (or, more generally, of lexical items) that have similar grammatical properties. Words that are assigned to the same part of speech generally display similar syntactic behavior (they play similar roles within the grammatical structure of sentences), sometimes similar morphological behavior in that they undergo inflection for similar properties and even similar semantic behavior. Commonly listed English parts of speech are noun, verb, adjective, adverb, pronoun, preposition, conjunction, interjection, numeral, article, and determiner. Other terms than ''part of speech''—particularly in modern linguistic classifications, which often make more precise distinctions than the traditional scheme does—include word class, lexical class, and lexical category. Some authors restrict the term ''lexical category'' to refer only to a par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Linguistics
Structural linguistics, or structuralism, in linguistics, denotes schools or theories in which language is conceived as a self-contained, self-regulating semiotic system whose elements are defined by their relationship to other elements within the system. It is derived from the work of Swiss linguist Ferdinand de Saussure and is part of the overall approach of structuralism. Saussure's '' Course in General Linguistics'', published posthumously in 1916, stressed examining language as a dynamic system of interconnected units. Saussure is also known for introducing several basic dimensions of semiotic analysis that are still important today. Two of these are his key methods of syntagmatic and paradigmatic analysis, which define units syntactically and lexically, respectively, according to their contrast with the other units in the system. Other key features of structuralism are the focus on systematic phenomena, the primacy of an idealized form over actual speech data, the priori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic Programming
Logic programming is a programming, database and knowledge representation paradigm based on formal logic. A logic program is a set of sentences in logical form, representing knowledge about some problem domain. Computation is performed by applying logical reasoning to that knowledge, to solve problems in the domain. Major logic programming language families include Prolog, Answer Set Programming (ASP) and Datalog. In all of these languages, rules are written in the form of ''clauses'': :A :- B1, ..., Bn. and are read as declarative sentences in logical form: :A if B1 and ... and Bn. A is called the ''head'' of the rule, B1, ..., Bn is called the ''body'', and the Bi are called '' literals'' or conditions. When n = 0, the rule is called a ''fact'' and is written in the simplified form: :A. Queries (or goals) have the same syntax as the bodies of rules and are commonly written in the form: :?- B1, ..., Bn. In the simplest case of Horn clauses (or "definite" clauses), all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
