In computer science , a recursivedescentparser is a kind of Top down parsing top down parsing parser built from a set of Mutual recursion mutually recursive procedures or a non recursive equivalent where ... it recognizes. A predictive parser is a recursivedescentparser that does not require backtracking . Predictive parsing is possible only for the class of LL parser LL k grammars, which are the context free grammar s for which there exists some positive integer k that allows a recursivedescent ... Monadic Parsing in Haskell See also Portal Computer Science JavaCC a recursivedescentparser generator Coco R a recursivedescentparser generator ANTLR a recursivedescentparser generator Parsing expression grammar another form representing recursivedescent grammar Spirit Parser Framework a C recursivedescentparser generator framework requiring no pre compile step Tail recursiveparser a variant of the recursivedescentparser Parboiled Java parboiled a recursivedescent PEG parsing library for Java Recursive ascent parser References No footnotes date February 2009 FOLDOC Compilers Principles ... on recursivedescent parsing http teaching.idallen.com cst8152 98w recursive decent parsing.html How to turn a Grammar into C code a brief tutorial on implementing recursivedescentparser http partow.net programming exprtk index.html ExprTk Recursivedescent mathematical expression parser and evaluator ... in linear time . Recursivedescent with backup is a technique that determines which production to use by trying each production in turn. Recursivedescent with backup is not limited to LL k grammars ... recursivedescent with backup may require exponential time . Although predictive parsers are widely ... descentparser for the above language in C programming language C . The parser reads in source ... period source Implementation in functional languages Recursivedescent parsers are particularly ... language Python recursive parsing module that is not recursivedescent http mail.python.org pipermail ... more details
?pgno 1 Article in the January 2006 edition of Dr. Dobbs Journal, RecursiveDescent, Tail Recursion ...wikify date December 2011 In computer science , tail recursive parsers are a derivation from the more common recursivedescentparser s. Tail recursive parsers are commonly used to parse left recursive grammars. They use a smaller amount of stack space than regular recursivedescent parsers. They are also easy to write. Typical recursivedescent parsers make parsing left recursive grammars impossible because of an infinite loop problem . Tail recursive parsers use a node reparenting technique that makes this allowable. Given an EBNF Grammar such as the following E T T T F F F F I I I identifier A simple tail recursiveparser can be written much like a recursivedescentparser. The typical algorithm for parsing a grammar like this using an Abstract syntax tree is Parse the next level of the grammar and get its output tree, designate it the first tree, F While there is terminating token, T, that can be put as the parent of this node Allocate a new node, N Set N s current operator as the current input token Advance the input one token Set N s left subtree as F Parse another level down again and store this as the next tree, X Set N s right subtree as X Set F to N Return N A C programming language implementation of this parser is shown here source lang c typedef struct exptree exptree struct exptree char token exptree left exptree right exptree parse e void return parse t exptree parse t void exptree first f parse f while cur token exptree replace tree alloc tree replace tree token cur token replace tree left first f next token replace tree right parse f first f replace tree return first f exptree parse f void exptree first i parse i while cur token exptree replace tree alloc tree replace tree token cur token replace tree left first i next token replace tree right parse i first i replace tree return first i exptree parse i void exptree i alloc tree exptree left exptree right ... more details
In computer science , recursive ascent parsing is a technique for implementing an LALR parser which uses mutually recursive functions rather than tables. Thus, the parser is directly encoded in the host language similar to recursivedescent . Direct encoding usually yields a parser which is faster than ... bottom up. It can also yield some minimal performance improvements over conventional recursive ascent ref cite web title ScalaBison Recursive Ascent DescentParser Generator author John Boyland and Daniel ... 0 res, goto 1 source See also RecursivedescentparserRecursive ascent descentparser References reflist ... than interpretation. It is also nominally possible to hand edit a recursive ascent parser, whereas a tabular implementation is nigh unreadable to the average human. Recursive ascent was first ... of an LR parser, but rather a maintainable and efficient parser implemented in assembly language . The technique was later expounded upon by G.H. Roberts ref cite web title Recursive ascent an LR analog to recursivedescent year 1988 author G.H. Roberts url http portal.acm.org citation.cfm?id 47907.47909 ... ref . Recursive ascent has also been merged with recursivedescent, yielding a technique known as recursive ascent descent . This implementation technique is arguably easier to hand edit due to the reduction ..., recursive ascent is a literal implementation of the LR parser LR parsing concept. Each function in the parser represents a single LR Finite state machine automaton state. Within each function, a multi ... of a recursive ascent parser based on the above grammar source lang scala object ExprParser private ... title A functional LR parser author Leermakers, Augusteijn, Kruseman Aretz year 1992 url http portal.acm.org ... title Recursive ascent parsing author Larry Morell and David Middleton year 2003 journal Journal of Computing ... LR 0 versus SLR and LALR parsing LR 0 in that it is left recursive in the expr non terminal but does not require any lookahead. Recursive ascent is also capable of handling grammars which are LALR 1 ... more details
In computer science , a Pratt parser is an improved recursivedescentparser that associates semantics with tokens instead of grammar rules. ref http effbot.org zone simple top down parsing.htm Simple Top Down Parsing in Python ref It was first described by Vaughan Pratt in the 1973 paper Top down operator precedence ref Pratt, Vaughan. http portal.acm.org citation.cfm?id 512931 Top down operator precendence . Proceedings of the 1st Annual ACM SIGACT SIGPLAN Symposium on Principles of Programming Languages 1973 . ref , and was treated in much more depth in a Masters Thesis under his supervision ref Van De Vanter, Michael L. http publications.csail.mit.edu lcs specpub.php?id 715 A Formalization and Correctness Proof of the CGOL Language System . Master s Thesis . MIT Laboratory for Computer Science Technical Report MIT LCS TR 147 Cambridge, MA . 1975. ref . Pratt designed the parser originally to implement the CGOL programming language. Douglas Crockford used the technique to build JSLint . Notes Reflist Category Parsing algorithms algorithm stub ... more details
, the recursivedescentparser defaults perhaps unknown to the grammar designer to one of the possible ... of memo table throughout the computation. Like any top down Recursivedescentparserrecursivedescent ... representing locations in the string where parsing stopped successfully. Parser combinators enable a recursivedescent parsing strategy which facilitates modular piecewise construction and testing ... 2008 Frost, R., Hafiz, R. and Callaghan, P. Parser Combinators for Ambiguous Left Recursive Grammars ..., like all recursivedescent parsers , are not limited to the context free grammar s and thus do ...In functional programming , a parser combinator is a higher order function which accepts several parsers as input and returns a new parser as its output. In this context, a parser is a function accepting ... Volume 32, Issue 2. Pages 108 121, 1989 ref use of parser combinators to construct natural language ... 2 Issue 3, Pages 323 343, 1992. ref S.D. Swierstra also exhibited the practical aspects of parser ... , Volume 4902, year 2008, Pages 167 181, January 2008, San Francisco. ref a set of parser combinators ... In functional programming , parser combinators can be used to combine basic parsers to construct parsers ... parser is available for each of these alternatives, a parser combinator can be used to combine each of these parsers, returning a new parser which can recognise any or all of the alternatives. A parser combinator can take the form of an infix operator, used to glue different parsers to form a complete rule. Parser combinators thereby enable parsers to be defined in an embedded style, in code ... the discussion relatively straightforward, we discuss parser combinators in terms of recognizers only ... j code , a recognizer is a parser which returns, as output, a set of indices representing positions at which the parser successfully finished recognizing a sequence of tokens that began at position ... successfully. The code empty code recognizer recognizes the empty string. This parser always ... more details
describes the table based kind of parser, the alternative being a recursivedescentparser which is usually coded by hand although not always see e.g. ANTLR for an LL recursivedescentparser generator . An LL parser is called an LL k parser if it uses k token parser tokens of lookahead when parsing a sentence. If such a parser exists for a certain grammar and it can parse sentences of this grammar ...In computer science , an LL parser is a Top down parsing top down parser for a subset of the context ... and syntax trees L eftmost derivation of the sentence hence LL, compared with LR parser . The class ... true now given the availability and widespread use Citation needed date August 2009 of parser generators supporting LL k grammars for arbitrary k . An LL parser is called an LL parser if it is not restricted ... Automaton . General case The parser works on strings from a particular context free grammar . The parser ... to apply given the symbols on top of its stack and the next input token The parser applies the rule ... stream column . When the parser starts, the stack already contains two symbols S, where is a special ... symbol of the grammar. The parser will attempt to rewrite the contents of this stack to what it sees ... to indicate the end of the input stream. Parsing procedure In each step, the parser reads the next ... symbol and the stack top symbol match, the parser discards them both, leaving only the unmatched symbols in the input stream and on the stack. Thus, in its first step, the parser reads the input symbol ... symbol and the row headed by the stack top symbol S this cell contains 2 , which instructs the parser to apply rule 2 . The parser has to rewrite S to S F on the stack and write the rule number 2 ... for the following step. In the second step, the parser removes the from its input stream and from its stack, since they match. The stack now becomes S, , F, , Now the parser has an a on its input stream ... the rule number 1 to the output stream. The stack becomes F, , F, , The parser now has an a on its ... more details
in Time complexity Time and space complexity time as a recursive ascent parser , a set of mutually recursive functions for every grammar, much like a recursivedescentparser . Conventionally, however ... a.k.a. terminals . An LR parser is based on an algorithm which is driven by a parsing table , a data structure which contains the syntax of the computer language being parsed. So the term LR parser actually refers to a class of parser that can process almost any programming language, as long as the parser table for a programming language is supplied. The parser table is created by a program called a parser generator. Architecture of LR parsers Image LR Parser.png right framed Figure 1. Architecture of a table based Bottom up parsing bottom up parser. Conceptually, an LR Parser is a recursive ... parser is a parser that reads input from L eft to right as it would appear if visually displayed and produces a Rightmost derivation R ightmost derivation . The term LR k parser is also used where the k ... decisions. Usually k is 1 and the term LR parser is often intended to refer to this case. LR .... This is in contrast to an LL k or even worse, an LL parser which may defer error detection to a different ... constructed by a parser generator or a compiler compiler . Depending on how the parsing table is generated, these parsers can be called simple LR parser s SLR , LALR parser look ahead LR parsers LALR , or canonical LR parser s. LALR parsers have more language recognition power than SLR parsers ... code . An LR parser can be created from a context free grammar by a program called a parser generator ... k parser for it, as determined by the parser generator. An LR parser is said to perform bottom up ... recursive program is explicitly manipulated. A Parsing table table driven bottom up parser can be schematically presented as in Figure 1. The following describes a rightmost derivation by this parser. General case The parser is a state machine. It consists of an input Buffer computer ... more details
distinguish Dissent wiktionary descentDescent may refer to In genealogy and inheritance Common descent , concept in evolutionary biology Kinship and descent , one of the major concepts of cultural anthropology ... diagram disambiguation Inheritance law and property In mathematics Infinite descent , a method going back to Fermat to solve Diophantine equations Descent category theory , an idea extending the notion of gluing in topology Hadamard s method of descent , a technique for solving partial differential equations Gradient descent , a first order optimization algorithm going back to Newton Other uses Descent aircraft , the decrease of an aircraft in altitude during flight Descent font , the distance that a typeface descends below the baseline in typography As a proper name In film The Descent , a 2005 horror film The Descent Part 2 , the 2009 sequel to the 2005 film Descent 2005 film Descent 2005 film , a television film on the Sci Fi Channel Descent 2007 film Descent 2007 film , a thriller starring Rosario Dawson In gaming Descent video game Descent video game , first in a series from Interplay Entertainment and Parallax Software Descent II , sequel to DescentDescent 3 , sequel to Descent II Descent FreeSpace The Great War , a computer game by Volition Inc Descent Journeys in the Dark , a 2005 board game by Fantasy Flight Games In literature The Descent novel The Descent novel , by Jeff Long Descent , caving magazine from Wild Places Publishing first published in 1969 In music Descent , an album by the band This Burning Effigy In television Descent The Outer Limits Descent The Outer Limits , an episode of the science fiction television series The Outer Limits Descent Stargate SG 1 Descent Stargate SG 1 , an episode of the science fiction television series Stargate SG 1 Descent Star Trek The Next Generation Descent Star Trek The Next Generation , a two part episode of Star Trek The Next Generation See also Dissent homophone disambiguation de Descent fr Descent hu Descent egy rtelm s t ... more details
dablink For the book by Jeff Long, see The Descent novel . For other similarly named films, see Descent 2005 film and Descent 2007 film . For other uses, see Descent . Infobox film name The Descent image ... http boxofficemojo.com movies ?id descent.htm ref The Descent is a 2005 British horror film written ... at the studio. The Descent opened commercially 8 July 2005 in the United Kingdom. It premiered in the 2006 ... reviews 2 film 4369 fall frights the descent film review.html Fall Frights THE DESCENT ... wary of being typecast as a horror film director, though he eventually agreed to make The Descent , emphasizing ... Filming While The Descent was set in North America, the film was shot entirely in the United Kingdom ... film The Thing , and Deliverance as influences in establishing tension in The Descent . The director ... t get any worse, make it worse. ref name blues Simon Bowles designed the maze of caves for The Descent ... rock that was developed for this production. Production of The Descent was in competition with an American film of a similar premise, The Cave film The Cave . The Descent was originally scheduled to be released ... before its competitor. Filmmakers of The Descent decided to release the film before The Cave , so ... The Descent was released in North America with approximately a minute cut from the end. In the American ... America , the Descent retains the original ending, with Sarah awakening back in the cave facing her ... File Crawlies.jpg 350 px caption Crawlers, as portrayed in The Descent left and The Descent 2 right classification Cave dwelling hominid first The Descent last The Descent Part 2 created by Neil ... Director Neil Marshall first chose to have a dark cave as the setting for his horror film The Descent ... last Morrison title Descent into hell work The Northern Echo publisher Newsquest date 2005 07 07 ref ... of The Descent 2 work Fangoria publisher Starlog Group accessdate 2008 06 26 archiveurl http web.archive.org ... News Corporation date 2006 12 16 ref The crawlers reappear in The Descent Part 2 , a sequel by Jon ... more details
In mathematics , specifically set theory , an ordinal number ordinal math alpha math is said to be recursive if there is a recursive set recursive well order ing of a subset of the natural numbers having the order type math alpha math . It is trivial to check that math omega math is recursive, the successor ordinal successor of a recursive ordinal is recursive, and the Set mathematics set of all recursive ordinals is closure mathematics closed downwards. The supremum of all recursive ordinals is called the Church Kleene ordinal and denoted by math omega CK 1 math . Indeed, an ordinal is recursive if and only if it is smaller than math omega CK 1 math . Since there are only countably many recursive relations, there are also only countable countably many recursive ordinals. Thus, math omega CK 1 math is countable. The recursive ordinals are exactly the ordinals that have an ordinal notation in Kleene s O Kleene s math mathcal O math . See also Arithmetical hierarchy Large countable ordinals Ordinal notation References Rogers, H. The Theory of Recursive Functions and Effective Computability , 1967. Reprinted 1987, MIT Press, ISBN 0 262 68052 1 paperback , ISBN 0 07 053522 1 Sacks, G. Higher Recursion Theory . Perspectives in mathematical logic, Springer Verlag, 1990. ISBN 0 387 19305 7 Category Set theory Category Computability theory Category Ordinal numbers settheory stub ... more details
Unreferenced date March 2009 A recursive call is a system call that must be completed before the completion of user s SQL statement. Basically, recursive calls are generated by Oracle Database Oracle internal sql statements to maintain changes to tables for internal processing. Reasons for Recursive Calls Recursive calls can be generated due to following reasons Dictionary cache is too small resulting in misses on cache Database Trigger Firing Performing DDL PL SQL blocks containing sql statements Category Computing terminology ... more details
In computer science , an LALR parser or look ahead LR parser is a type of LR parser based on a Finite ... date November 2011 used by an LALR parser is a pushdown automaton PDA . A deterministic PDA is a deterministic finite automaton DFA with the addition of a stack for a memory, indicating which states the parser ... of states due to unlimited nesting of parentheses. LALR parsers are driven by a parser table in a finite ... convenient to use a software tool called an LALR parser generator to generate a parser table automatically from a grammar in Backus Naur Form which defines the syntax of the computer language the parser ... author Levine, John Mason, Tony Brown, Doug. ref The parser table is often generated in source code format in a computer language such as C or Java . When the parser with parser table is compiled ... 2 grammar is adequate. If the parser generator handles only LALR 1 grammars, then the LALR parser will have ... offer the same high performance of LR parsers, and produce much smaller tables than the early LR parser ... . Compiler compilers such as Menhir and HYacc that generate true LR parser tables using Pager s algorithm ... LALR Parsers Similar to an SLR parser generator, an LALR parser generator constructs the LR 0 .... An SLR parser generator computes the lookahead sets by examining the BNF grammar these are called follow sets . However, an LALR parser generator computes the lookahead sets by examining the LR ... to cause a conflict ambiguity to be reported by the parser generator . Like SLR parser SLR , LALR is a refinement ... to an LR parser Items LR 0 item and a parser state. Specifically, the follow set for a given LR 0 item tt I tt in a given parser state tt S tt contains all symbols that are allowed by the grammar ... of parser states or right hand sides, therefore losing all context information. Because the lookahead ... An LALR parser can be automatically generated from an LALR grammar. An LALR grammar can be used to define many computer languages. An LALR parser is small. An LALR parser is fast if the parsing ... more details
Refimprove date December 2009 In computer science , a chart parser is a type of parsing parser suitable for ambiguous grammars including grammars of natural language s . It uses the dynamic programming approach partial hypothesized results are stored in a structure called a chart data structure chart and can be re used. This eliminates backtracking and prevents a combinatorial explosion . Chart parsing was developed by Martin Kay . ref cite web url http webdocs.cs.ualberta.ca lindek 650 papers chartParsing.pdf title Chart Parsing accessdate 20 November 2011 ref Types of chart parsers A common approach is to use a variant of the Viterbi algorithm . The Earley parser is a type of chart parser mainly used for parsing in computational linguistics , named for its inventor. Another chart parsing algorithm is the Cocke Younger Kasami algorithm Cocke Younger Kasami CYK algorithm. Chart parsers can also be used for parsing computer languages. Earley parsers in particular have been used in compiler compiler s where their ability to parse using arbitrary Context free grammars eases the task of writing the grammar for a particular language. However their lower efficiency has led to people avoiding them for most compiler work. In bidirectional chart parsing , edges of the chart are marked with a direction, either forwards or backwards, and rules are enforced on the direction in which edges must point in order to be combined into further edges. In incremental chart parsing , the chart is constructed incrementally as the text is edited by the user, with each change to the text resulting in the minimal possible corresponding change to the chart. We can distinguish Top down parsing top down and bottom up parser bottom up chart parsers, and active chart parser active and passive chart parser ... reflist DEFAULTSORT Chart Parser Category Natural language parsing Category Parsing algorithms de Chart Parser es Chart parser ja ... more details
Infobox software name pdf parser logo released Start date 2008 05 02 author Didier Stevens latest release version 0.3.9 latest release date Start date and age 2012 03 11 programming language Python programming language operating system Multiplatform, including smart phones status Active genre Portable Document Format PDF software license Public domain website http blog.didierstevens.com programs pdf tools pdf parser Portal Free software pdf parser is a command line program that parses and analyses PDF documents. It provides features to extract raw data from PDF documents, like compressed images. pdf parser can deal with malicious PDF documents that use obfuscation features of the PDF language ref http isc.sans.edu diary.html?storyid 7984 PDF Babushka by Bojan Zdrnja, Internet Storm Center , January 14, 2010 ref . The tool can also be used to extract data from damaged or corrupt PDF documents. References Reflist Category PDF software ... more details
An inverse parser , as its name suggests, is a parser that works in reverse. Rather than the user typing into the computer, the computer presents a list of words fitting the context, and excludes words that would be unreasonable. This ensures the user knows all of his or her options. The concept and an implementation were originally developed and patent ed by Texas Instruments . A few years later, it was independently developed by Chris Crawford game designer Chris Crawford , a game designer, for his game, Trust & Betrayal The Legacy of Siboot , but the implementation was different enough not to infringe on the patent. External links http www.erasmatazz.com page78 page31 page303 page306 InverseParser.html How to Build an Inverse Parser , an essay by Chris Crawford originally published in the Journal of Computer Game Design Category Parsing comp sci stub ... more details
In signal processing , a recursive filter is a type of filter signal processing filter which re uses one or more of its outputs as an input. This feedback typically results in an unending impulse response commonly referred to as infinite impulse response IIR , characterised by either exponential growth exponentially growing , exponential decay decaying , or sinusoid al signal output components. However, a recursive filter does not always have an infinite impulse response. Some implementations of moving average filter are recursive filters but with a Finite impulse response. Examples of recursive filters Kalman filter Category Signal processing electronics stub statistics stub economics stub ... more details
In computability theory , a Set mathematics set of natural number s is called recursive , computable or decidable if there is an algorithm which terminates after a finite amount of time and correctly decides whether or not a given number belongs to the set. A more general class of sets consists of the recursively enumerable set s, also called semidecidable sets. For these sets, it is only required that there is an algorithm that correctly decides when a number is in the set the algorithm may give no answer but not the wrong answer for numbers not in the set. A set which is not computable is called noncomputable or undecidable . Formal definition A subset math var S var of the natural number s is called recursive if there exists a total function total computable function math f such that math f var x var 1 if math var x var &isin var S var and math f var x var 0 if math var x var ¬in var S var . In other words, the set math var S var is recursive if and only if the indicator function .... A recursive language is a recursive subset of a formal language . The set of G del numbers ... Mathematica and related systems I see G del s incompleteness theorems . Properties If A is a recursive set then the complement set theory complement of A is a recursive set. If A and B are recursive sets then A B , A B and the image of A × B under the Cantor pairing function are recursive sets. A set A is a recursive set if and only if A and the complement set theory complement of A are both recursively enumerable set s. The preimage of a recursive set under a total function total computable function is a recursive set. The image of a computable set under a total computable bijection is computable. A set is recursive if and only if it is at level math &Delta su p 0 b 1 of the arithmetical hierarchy . A set is recursive if and only if it is either the range of a nondecreasing ..., Cambridge New York, 1980. ISBN 0 521 22384 9 ISBN 0 521 29465 7 Rogers, H. The Theory of Recursive ... more details
No footnotes date May 2011 In computer science , a GLR parser Generalized Left to right Rightmost derivation parser is an extension of an LR parser algorithm to handle nondeterministic and ambiguous grammars . First 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 ref Masaru Tomita. Efficient parsing for natural language. Kluwer Academic Publishers, Boston, 1986. ref , though, in practice, it is the second stage that is recognized as the GLR parser. Though the algorithm has evolved since its original form, the principles have remained intact Tomita s goal was to parse natural language text thoroughly and efficiently. Standard LR parsers cannot accommodate the nondeterministic and ambiguous nature of natural language , and the GLR algorithm can. Algorithm Briefly, the GLR algorithm works in a manner similar to the LR parser algorithm, except that, given a particular grammar, a GLR parser will process all possible interpretations of a given input in a breadth first search . On the front end, a GLR parser generator converts an input grammar into parser tables, in a manner similar to an LR generator. However, where LR parse tables allow for only one state transition given a state and an input token , GLR parse tables allow for multiple transitions. In effect, GLR allows for shift reduce and reduce reduce conflicts. When a conflicting transition is encountered, the parse stack is forked into two or more parallel parse stacks, where the state corresponding to each possible transition is at the top. Then, the next input token is read and used to determine the next transition s for each ... parser, allowing still higher performance ref cite web title Elkhound, Elsa and Cqual Open Source ... of parser generators ASF SDF Meta Environment DMS Software Reengineering Toolkit References ... Category Parsing algorithms de Tomita Parser ja GLR pl Parser GLR pt Analisador sint tico GLR ru GLR ... more details
In graph theory , a discipline within mathematics, a recursive tree i.e., unordered tree is a non planar labeled rooted tree graph theory tree . A size n recursive tree is labeled by distinct integers 1, 2, ..., n , where the labels are strictly increasing starting at the root labeled 1. Recursive trees are non planar, which means that the children of a particular node are not ordered. E.g. the following two size three recursive trees are the same. pre 1 1 2 3 3 2 pre Recursive trees also appear in the literature under the name Increasing Cayley trees. Properties The number of size n recursive trees is given by math T n n 1 . , math Hence the exponential generating function T z of the sequence T sub n sub is given by math T z sum n ge 1 T n frac z n n log left frac 1 1 z right . math Combinatorically a recursive tree can be interpreted as a root followed by an unordered sequence of recursive trees. Let F denote the family of recursive trees. math F circ frac 1 1 cdot circ times F frac 1 2 cdot circ times F F frac 1 3 cdot circ times F F F cdots circ times exp F , math where math circ math denotes the node labeled by 1, × the Cartesian product and math math the partition product for labeled objects. By translation of the formal description one obtains the differential equation for T z math T z exp T z , math with T 0 0. Bijections There are bijection bijective correspondences between recursive trees of size n and permutation s of size n &minus 1. Applications Recursive trees can be generated using a simple stochastic process. Such random recursive trees are used as simple models for epidemics. References Analytic Combinatorics , Philippe Flajolet and Robert Sedgewick, Cambridge University Press, 2008 Varieties of Increasing Trees , Francois ... of random recursive trees and binary search trees Michael Drmota and Hsien Kuei Hwang, Adv. Appl. Prob., 37, 1 21, 2005. Profiles of random trees Limit theorems for random recursive trees and binary ... more details
Chomsky 1959 . All recursive languages are also recursively enumerable language recursively enumerable ... context sensitive languages are recursive. Definitions There are two equivalent major definitions for the concept of a recursive language A recursive formal language is a recursive set recursive subset ... . A recursive language is a formal language for which there exists a Turing machine which will, when ... halts decider and is said to decide the recursive language. By the second definition, any ... inputs. An undecidable problem is a problem that is not decidable. Closure properties Recursive ... recursive languages, then the following languages are recursive as well The Kleene star math L math ... more details
Unreferenced date December 2006 Orphan date February 2009 The recursive join is an operation used in relational databases , also sometimes called a fixed point join . It is a compound operation that involves repeating the join SQL join operation, typically accumulating more records each time, until a repetition makes no change to the results as compared to the results of the previous iteration . For example, if a database of family relationships is to be searched, and the record for each person has mother and father fields, a recursive join would be one way to retrieve all of a person s known ancestors first the person s direct parents records would be retrieved, then the parents information would be used to retrieve the grandparents records, and so on until no new records are being found. In this example, as in many real cases, the repetition involves only a single database table, and so is more specifically a recursive self join . Recursive joins can be very time consuming unless optimized through indexing, the addition of extra key fields, or other techniques. Recursive joins are highly characteristic of hierarchical data, and therefore become a serious issue with XML data. In XML, operations such as determining whether one element contains another are extremely common, and the recursive join is perhaps the most obvious way to implement them when the XML data is stored in a relational database. See also Join SQL Join Category Database theory Category Relational model Comp sci stub ... more details
Parser New Poetry & Poetics is an annual journal of anarchist poetry and poetics from Vancouver, BC, edited by Roger Farr and Reg Johanson . The first issue was published in May 2007, featuring writing by Alice Becker Ho , Alfredo M. Bonanno , P. Inman , Dorothy Trujillo Lusk, Aaron Vidaver, and Rita Wong. External links http www.parsermag.org Official website http robmclennan.blogspot.com 2007 11 p r s e r new poetry poetics may 2007.html Review of PARSER 1 Category Canadian literary magazines Category Anarchist periodicals Category Canadian cultural magazines Category Publications established in 2007 poli mag stub Canada lit mag stub ... more details
Recursive function may refer to Recursion computer science , a procedure or subroutine, implemented in a programming language, whose implementation references itself A total computable function , a function which is defined for all possible inputs See also recursive function , defined from a particular formal model of computable functions using primitive recursion and the operator Recurrence relation , in mathematics, an equation that defines a sequence recursively disambig Category Recursion cs Rekurzivn funkce ru ... more details
Orphan date February 2009 Cleanup date February 2008 Recursive economics is a branch of modern economics based on highly complex mathematical function . The mathematical model model s are based on dynamical system dynamic differential equation s. This approach has been popularised by Robert Lucas, Jr. and Edward Prescott . Books Recursive Methods in Economic Dynamics by Nancy L. Stokey, Robert E. Lucas, Jr., Edward C. Prescott, Harvard 1989 economics stub Category Mathematical economics ... more details
for information about parsing in general Parsing Refimprove date August 2007 In adventure game s, a text parser takes typed input a command from the player and simplifies it to something the game can understand. Usually, words with the same meaning are turned into the same word e.g. take and get and certain filler words are dropped e.g. articles, or the at in look at rock . The parser makes it easier for the game s author to react on input. The author does not have to write special code to process the commands get the gem , take the gem , get gem , take gem , take the precious gem , etc separately, as the parser will have stripped the input down to something like take gem . For the player, the game is more flexible, as the game has a larger vocabulary, and there are fewer guess the verb and guess the noun problems. Parsers are used in early interactive fiction games like the Zork series, and more recently in games created by systems like Inform and TADS . External links http www.inform fiction.org manual download dm4.html Inform Designers Manual in particular, see chapter 4, Describing and Parsing , and chapter 5, Natural Language Category Parsing Category Interactive fiction PAGENAME ... more details
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