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Re2c
re2c is a free and open-source lexer generator for C, C++, D, Go, Haskell, Java, JavaScript, OCaml, Python, Rust, V and Zig. It compiles declarative regular expression specifications to deterministic finite automata. Originally written by Peter Bumbulis and described in his paper, re2c was put in public domain and has been since maintained by volunteers. It is the lexer generator adopted by projects such as PHP, SpamAssassin, Ninja build system and others. Together with the Lemon parser generator, re2c is used in BRL-CAD. This combination is also used with STEPcode, an implementation of ISO 10303 standard. Philosophy The main goal of re2c is generating ''fast'' lexers: at least as fast as reasonably optimized C lexers coded by hand. Instead of using traditional table-driven approach, re2c encodes the generated finite-state machine directly in the form of conditional jumps and comparisons. The resulting program is faster than its table-driven counterpart and much easier t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lemon (parser Generator)
Lemon is a parser generator, maintained as part of the SQLite project, that generates a ''look-ahead LR parser'' (LALR parser) in the programming language C from an input context-free grammar. The generator is quite simple, implemented in one C source file with another file used as a template for output. Lexical analysis is performed externally. Lemon is similar to the programs Bison and Yacc, but is incompatible with both. The grammar input format is different, to help prevent common coding errors. Other distinctive features include a reentrant, thread-safe output parser, and the concept of ''non-terminal destructors'' that try to make it easier to avoid memory leaks. SQLite uses Lemon with a hand-coded tokenizer to parse SQL strings. Lemon, together with re2c and a re2c wrapper named Perplex, are used in BRL-CAD as platform-agnostic and easily compilable alternatives to Flex and Bison. This combination is also used with STEPcode. OpenFOAM expression evaluation uses a com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GitHub
GitHub () is a Proprietary software, proprietary developer platform that allows developers to create, store, manage, and share their code. It uses Git to provide distributed version control and GitHub itself provides access control, bug tracking system, bug tracking, software feature requests, task management, continuous integration, and wikis for every project. Headquartered in California, GitHub, Inc. has been a subsidiary of Microsoft since 2018. It is commonly used to host open source software development projects. GitHub reported having over 100 million developers and more than 420 million Repository (version control), repositories, including at least 28 million public repositories. It is the world's largest source code host Over five billion developer contributions were made to more than 500 million open source projects in 2024. About Founding The development of the GitHub platform began on October 19, 2005. The site was launched in April 2008 by Tom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Domain
The public domain (PD) consists of all the creative work to which no Exclusive exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly Waiver, waived, or may be inapplicable. Because no one holds the exclusive rights, anyone can legally use or reference those works without permission. As examples, the works of William Shakespeare, Ludwig van Beethoven, Miguel de Cervantes, Zoroaster, Lao Zi, Confucius, Aristotle, L. Frank Baum, Leonardo da Vinci and Georges Méliès are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by a country's copyright laws, and are therefore in the public domain; for example, in the United States, items excluded from copyright include the formulae of Classical mechanics, Newtonian physics and cooking recipes. Other works are actively dedicated by their authors to the public domain (see waiver) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lex (software)
Lex is a computer program that generates lexical analyzers ("scanners" or "lexers"). It is commonly used with the yacc parser generator and is the standard lexical analyzer generator on many Unix and Unix-like systems. An equivalent tool is specified as part of the POSIX standard. Lex reads an input stream specifying the lexical analyzer and writes source code which implements the lexical analyzer in the C programming language. In addition to C, some old versions of Lex could generate a lexer in Ratfor. History Lex was originally written by Mike Lesk and Eric Schmidt and described in 1975. In the following years, Lex became the standard lexical analyzer generator on many Unix and Unix-like systems. In 1983, Lex was one of several UNIX tools available for Charles River Data Systems' UNOS operating system under Bell Laboratories license. Although originally distributed as proprietary software, some versions of Lex are now open-source. Open-source versions of Lex, based on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ragel
Ragel ( IPA: ) is a finite-state machine compiler and a parser generator. Initially Ragel supported output for C, C++ and Assembly source code, later expanded to support several other languages including Objective-C, D, Go, Ruby, and Java. Additional language support is also in development. It supports the generation of table or control flow driven state machines from regular expressions and/or state charts and can also build lexical analysers via the longest-match method. Ragel specifically targets text parsing and input validation.Omar Badreddin (2010) " Umple: a model-oriented programming language." ''Software Engineering, 2010 ACM/IEEE 32nd International Conference on. Vol. 2''. IEEE, 2010. Overview Ragel supports the generation of table or control flow driven state machines from regular expressions and/or state charts and can also build lexical analysers via the longest-match method. A unique feature of Ragel is that user actions can be associated with arbitrary st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flex (lexical Analyser Generator)
Flex (fast lexical analyzer generator) is a free and open-source software alternative to lex. It is a computer program that generates lexical analyzers (also known as "scanners" or "lexers"). It is frequently used as the lex implementation together with Berkeley Yacc parser generator on BSD-derived operating systems (as both lex and yacc are part of POSIX), or together with GNU bison (a version of yacc) in *BSD ports and in Linux distributions. Unlike Bison, flex is not part of the GNU Project and is not released under the GNU General Public License, although a manual for Flex was produced and published by the Free Software Foundation. History Flex was written in C around 1987 by Vern Paxson, with the help of many ideas and much inspiration from Van Jacobson. Original version by Jef Poskanzer. The fast table representation is a partial implementation of a design done by Van Jacobson. The implementation was done by Kevin Gong and Vern Paxson. Example lexical analyzer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOT (graph Description Language)
DOT is a Graph (discrete mathematics), graph description language, developed as a part of the Graphviz project. DOT graphs are typically stored as Computer file, files with the .gv or .dot filename extension — .gv is preferred, to avoid confusion with the .dot extension used by versions of Microsoft Word before 2007. dot is also the name of the main program to process DOT files in the Graphviz package. Various programs can process DOT files. Some, such as ''dot'', ''neato'', ''twopi'', ''circo'', ''fdp'', and ''sfdp'', can read a DOT file and render it in graphical form. Others, such as ''gvpr'', ''gc'', ''acyclic'', ''ccomps'', ''sccmap'', and ''tred'', read DOT files and perform calculations on the represented graph. Finally, others, such as ''lefty'', ''dotty'', and ''grappa'', provide an interactive interface. The GVedit tool combines a text editor and a non-interactive viewer. Most programs are part of the Graphviz package or use it internally. DOT is historically an acron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deterministic Finite Automaton
In the theory of computation, a branch of theoretical computer science, a deterministic finite automaton (DFA)—also known as deterministic finite acceptor (DFA), deterministic finite-state machine (DFSM), or deterministic finite-state automaton (DFSA)—is a finite-state machine that accepts or rejects a given string of symbols, by running through a state sequence uniquely determined by the string. ''Deterministic'' refers to the uniqueness of the computation run. In search of the simplest models to capture finite-state machines, Warren McCulloch and Walter Pitts were among the first researchers to introduce a concept similar to finite automata in 1943. The figure illustrates a deterministic finite automaton using a state diagram. In this example automaton, there are three states: S0, S1, and S2 (denoted graphically by circles). The automaton takes a finite sequence of 0s and 1s as input. For each state, there is a transition arrow leading out to a next state for both 0 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nondeterministic Finite Automaton
In automata theory, a finite-state machine is called a deterministic finite automaton (DFA), if * each of its transitions is ''uniquely'' determined by its source state and input symbol, and * reading an input symbol is required for each state transition. A nondeterministic finite automaton (NFA), or nondeterministic finite-state machine, does not need to obey these restrictions. In particular, every DFA is also an NFA. Sometimes the term NFA is used in a narrower sense, referring to an NFA that is ''not'' a DFA, but not in this article. Using the subset construction algorithm, each NFA can be translated to an equivalent DFA; i.e., a DFA recognizing the same formal language. Like DFAs, NFAs only recognize regular languages. NFAs were introduced in 1959 by Michael O. Rabin and Dana Scott, who also showed their equivalence to DFAs. NFAs are used in the implementation of regular expressions: Thompson's construction is an algorithm for compiling a regular expression to an NFA that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DFA Minimization
In automata theory (a branch of theoretical computer science), DFA minimization is the task of transforming a given deterministic finite automaton (DFA) into an equivalent DFA that has a minimum number of states. Here, two DFAs are called equivalent if they recognize the same regular language. Several different algorithms accomplishing this task are known and described in standard textbooks on automata theory. Minimal DFA For each regular language, there also exists a minimal automaton that accepts it, that is, a DFA with a minimum number of states and this DFA is unique (except that states can be given different names). The minimal DFA ensures minimal computational cost for tasks such as pattern matching. There are three classes of states that can be removed or merged from the original DFA without affecting the language it accepts. * Unreachable states are the states that are not reachable from the initial state of the DFA, for any input string. These states can be removed. * D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finite-state Machine
A finite-state machine (FSM) or finite-state automaton (FSA, plural: ''automata''), finite automaton, or simply a state machine, is a mathematical model of computation. It is an abstract machine that can be in exactly one of a finite number of ''State (computer science), states'' at any given time. The FSM can change from one state to another in response to some Input (computer science), inputs; the change from one state to another is called a ''transition''. An FSM is defined by a list of its states, its initial state, and the inputs that trigger each transition. Finite-state machines are of two types—Deterministic finite automaton, deterministic finite-state machines and Nondeterministic finite automaton, non-deterministic finite-state machines. For any non-deterministic finite-state machine, an equivalent deterministic one can be constructed. The behavior of state machines can be observed in many devices in modern society that perform a predetermined sequence of actions d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO 10303
ISO 10303 (Automation systems and integration — Product data representation and exchange)ISO 10303-1:1994 Industrial automation systems and integration -- Product data representation and exchange -- Part 1: Overview and fundamental principles is a family of ISO standards for computer-interpretable representation (description) and exchange of product manufacturing information (PMI). It aims to provide interoperability between various computer-aided design (CAD) software, assist with automation in computer-aided manufacturing (CAM), and allows long-term archival of 3D, CAD and PDM data. It is known informally as "STEP", which stands for "''Standard for the Exchange of Product model data''". Due to a large scope ISO 10303 is subdivided into approximately 700 underlying standards total. The standard includes Parts 11-18 and Part 21 that describe EXPRESS data schema definition language and STEP-file (also STEP-XML) used for textual representation of PMI data codified by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
