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Perl Compatible Regular Expressions
Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. PCRE's syntax is much more powerful and flexible than either of the POSIX regular expression flavors (BRE, ERE) and than that of many other regular-expression libraries. While PCRE originally aimed at feature-equivalence with Perl, the two implementations are not fully equivalent. During the PCRE 7.x and Perl 5.9.x phase, the two projects coordinated development, with features being ported between them in both directions. In 2015, a fork of PCRE was released with a revised programming interface (API). The original software, now called PCRE1 (the 1.xx–8.xx series), has had bugs mended, but no further development. , it is considered obsolete, and the current 8.45 release is likely to be the last. The new PCRE2 code (the 10.xx series) has had a number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philip Hazel
Philip Hazel is a computer programmer best known for writing the Exim mail transport agent in 1995 and the PCRE regular expression library in 1997. He did undergraduate studies at the University of Cape Town and went to the University of Cambridge for his PhD. He arrived in Cambridge in 1967 where he was employed by the University of Cambridge Computing Service until he retired at the end of September 2007. In 2009 Hazel wrote an autobiographical memoir about his computing career which he updated in 2017. Hazel is also known for his typesetting software, in particular " Philip's Music Writer", as well as programs to turn a simple markup into a subset of DocBook XML for use in the Exim manual, and to produce PostScript PostScript (PS) is a page description language and dynamically typed, stack-based programming language. It is most commonly used in the electronic publishing and desktop publishing realm, but as a Turing complete programming language, it c ... from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maximal Munch
In computer programming and computer science, "maximal munch" or "longest match" is the principle that when creating some construct, as much of the available input as possible should be consumed. The earliest known use of this term is by R.G.G. Cattell in his PhD thesis on automatic derivation of Code generation (compiler), code generators for compilers. Application For instance, the lexical grammar, lexical syntax of many programming languages requires that Token (parser), tokens be built from the maximum possible number of characters from the input stream. This is done to resolve the problem of inherent ambiguity in commonly used regular expressions such as [a-z]+ (one or more lower-case letters). The term is also used in compilers in the instruction selection stage to describe a method of "tiling" — determining how a structured tree representing a program in an intermediate language should be converted into linear machine code. An entire subtree might be converted into just ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language) Libraries
C, or c, is the third letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''cee'' (pronounced ), plural ''cees''. History "C" comes from the same letter as "G". The Semites named it gimel. The sign is possibly adapted from an Egyptian hieroglyph for a staff sling, which may have been the meaning of the name ''gimel''. Another possibility is that it depicted a camel, the Semitic name for which was ''gamal''. Barry B. Powell, a specialist in the history of writing, states "It is hard to imagine how gimel = "camel" can be derived from the picture of a camel (it may show his hump, or his head and neck!)". In the Etruscan language, plosive consonants had no contrastive voicing, so the Greek ' Γ' (Gamma) was adopted into the Etruscan alphabet to represent . Already in the Western Greek alphabet, Gamma first took a '' form in Early Etruscan, then '' in Classical E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Cambridge
The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, world's third-oldest university in continuous operation. The university's founding followed the arrival of scholars who left the University of Oxford for Cambridge after a dispute with local townspeople. The two ancient university, ancient English universities, although sometimes described as rivals, share many common features and are often jointly referred to as Oxbridge. In 1231, 22 years after its founding, the university was recognised with a royal charter, granted by Henry III of England, King Henry III. The University of Cambridge includes colleges of the University of Cambridge, 31 semi-autonomous constituent colleges and List of institutions of the University of Cambridge#Schools, Faculties, and Departments, over 150 academic departm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Unicode Characters
As of Unicode version 16.0, there are 292,531 assigned character (computing), characters with code points, covering 168 modern and historical Script (Unicode), scripts, as well as multiple symbol sets. As it is WP:CHOKING, not technically possible to list all of these characters in a single Wikipedia page, this list is limited to a subset of the most important characters for English-language readers, with links to other pages which list the supplementary characters. This article includes the 1,062 characters in the Multilingual European Character Set 2 (MES-2) subset, and some additional related characters. Character reference overview HTML and XML provide ways to reference Unicode characters when the characters themselves either cannot or should not be used. A ''numeric character reference'' refers to a character by its Universal Character Set/Unicode ''code point'', and a ''character entity reference'' refers to a character by a predefined name. A ''numeric character refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Regular Expression Engines
This is a comparison of regular expression engines. Libraries Languages {, class="wikitable sortable" style="width: auto; table-layout: fixed;" , + List of languages and frameworks including regular expression support , - ! Language ! Official website ! Software license ! Remarks , - ! , ActionScript 3 ActionScript Technology Center, , style="text-align: left;" , , - ! , APL (APLX, Dyalog, GNU) APL Wiki, , style="text-align: left;" , ⎕SS (PCRE), ⎕R/⎕S (PCRE), ⎕SS (PCRE2), respectively , - ! , C++11 ( C++) C++ standards website, , style="text-align: left;" , Since ISO14822:2011(e), similar to ECMAScript on defaul(Grammar Description), - ! , D D, , style="text-align: left;" , , - ! , Elixir elixir-lang.org, style="text-align: center;" {{free, Apache 2.0 , style="text-align: left;" , Standard library includes PCRE-baseRegex module The matching algorithms of the library are based on the PCRE library, but not all of the PCRE library is inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grep
grep is a command-line utility for searching plaintext datasets for lines that match a regular expression. Its name comes from the ed command g/re/p (global regular expression search and print), which has the same effect. grep was originally developed for the Unix operating system, but later became available for all Unix-like systems and some others such as OS-9. History Before it was named, grep was a private utility written by Ken Thompson to search files for certain patterns. Doug McIlroy, unaware of its existence, asked Thompson to write such a program. Responding that he would think about such a utility overnight, Thompson actually corrected bugs and made improvements for about an hour on his own program called "s" (short for "search"). The next day he presented the program to McIlroy, who said it was exactly what he wanted. Thompson's account may explain the belief that grep was written overnight. Thompson wrote the first version in PDP-11 assembly language to help Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tab Key
The tab key (abbreviation of tabulator key or tabular key) on a keyboard is used to advance the cursor to the next tab stop. History The word ''tab'' derives from the word ''tabulate'', which means "to arrange data in a tabular, or table, form". When a person wanted to type a table (of numbers or text) on a typewriter, there was a lot of time-consuming and repetitive use of the space bar and backspace key. To simplify this, a horizontal bar was placed in the mechanism called the tabulator rack. Pressing the tab key would advance the carriage to the next tabulator stop. The original tabulator stops were adjustable clips that could be arranged by the user on the tabulator rack. Fredric Hillard filed a patent application for such a mechanism in 1900. The tab mechanism came into its own as a rapid and consistent way of uniformly indenting the first line of each paragraph. Often a first tab stop at 5 or 6 characters was used for this, far larger than the indentation used whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backtracking
Backtracking is a class of algorithms for finding solutions to some computational problems, notably constraint satisfaction problems, that incrementally builds candidates to the solutions, and abandons a candidate ("backtracks") as soon as it determines that the candidate cannot possibly be completed to a valid solution. The classic textbook example of the use of backtracking is the eight queens puzzle, that asks for all arrangements of eight chess queens on a standard chessboard so that no queen attacks any other. In the common backtracking approach, the partial candidates are arrangements of ''k'' queens in the first ''k'' rows of the board, all in different rows and columns. Any partial solution that contains two mutually attacking queens can be abandoned. Backtracking can be applied only for problems which admit the concept of a "partial candidate solution" and a relatively quick test of whether it can possibly be completed to a valid solution. It is useless, for exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oniguruma
is a free and open-source regular expression library that supports a variety of character encodings, written by K. Kosako. The Ruby programming language, in version 1.9, as well as PHP's multi-byte string module (since PHP5), use Oniguruma as their regular expression engine. It is also used in products such as Atom, EDK2 UEFI, GyazMail, Take Command Console, Tera Term, TextMate, SubEthaEdit and jq. As of April 26, 2025, development of Oniguruma was stopped and the project was archived. There used to be also a fork of Oniguruma called "Onigmo" (Oniguruma-mod) which includes some features introduced in Perl 5.10+. Ruby switched to it in version 2.0 and features have been backported from Ruby to Onigmo. Take Command Console from version 20 to version 32 used to Onigmo. Take Command switched back to Oniguruma in version 33 as Onigmo is no longer being updated. See also * Comparison of regular expression engines This is a comparison of regular expression engines. Libraries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Python (programming Language)
Python is a high-level programming language, high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is type system#DYNAMIC, dynamically type-checked and garbage collection (computer science), garbage-collected. It supports multiple programming paradigms, including structured programming, structured (particularly procedural programming, procedural), object-oriented and functional programming. It is often described as a "batteries included" language due to its comprehensive standard library. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC (programming language), ABC programming language, and he first released it in 1991 as Python 0.9.0. Python 2.0 was released in 2000. Python 3.0, released in 2008, was a major revision not completely backward-compatible with earlier versions. Python 2.7.18, released in 2020, was the last release of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicode Transformation Format
Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 characters and 168 scripts used in various ordinary, literary, academic, and technical contexts. Unicode has largely supplanted the previous environment of a myriad of incompatible character sets used within different locales and on different computer architectures. The entire repertoire of these sets, plus many additional characters, were merged into the single Unicode set. Unicode is used to encode the vast majority of text on the Internet, including most web pages, and relevant Unicode support has become a common consideration in contemporary software development. Unicode is ultimately capable of encoding more than 1.1 million characters. The Unicode character repertoire is synchronized with ISO/IEC 10646, each being code-for-code id ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
