|
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 (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 GNU Bison, 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 Reentrancy (computing), reentrant, Thread safety, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross-platform
In computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several computing platforms. Some cross-platform software requires a separate build for each platform, but some can be directly run on any platform without special preparation, being written in an interpreted language or compiled to portable bytecode for which the interpreters or run-time packages are common or standard components of all supported platforms. For example, a cross-platform application may run on Microsoft Windows, Linux, and macOS. Cross-platform software may run on many platforms, or as few as two. Some frameworks for cross-platform development are Codename One, Kivy, Qt, Flutter, NativeScript, Xamarin, Phonegap, Ionic, and React Native. Platforms ''Platform'' can refer to the type of processor (CPU) or other hardware on which an operating system (OS) or application runs, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reentrancy (computing)
In computing, a computer program or subroutine is called reentrant if multiple invocations can safely run concurrently on multiple processors, or on a single processor system, where a reentrant procedure can be interrupted in the middle of its execution and then safely be called again ("re-entered") before its previous invocations complete execution. The interruption could be caused by an internal action such as a jump or call, or by an external action such as an interrupt or signal, unlike recursion, where new invocations can only be caused by internal call. This definition originates from multiprogramming environments where multiple processes may be active concurrently and where the flow of control could be interrupted by an interrupt and transferred to an interrupt service routine (ISR) or "handler" subroutine. Any subroutine used by the handler that could potentially have been executing when the interrupt was triggered should be reentrant. Similarly, code shared by two process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M4 (computer Language)
m4 is a general-purpose macro processor included in most Unix-like operating systems, and is a component of the POSIX standard. The language was designed by Brian Kernighan and Dennis Ritchie for the original versions of UNIX. It is an extension of an earlier macro processor, m3, written by Ritchie for an unknown AP-3 minicomputer.Brian W. Kernighan and Dennis M. Ritchie. The m4 macro processor. Technical report, Bell Laboratories, Murray Hill, New Jersey, USA, 1977pdf/ref> The macro preprocessor operates as a text-replacement tool. It is employed to re-use text templates, typically in computer programming applications, but also in text editing and text-processing applications. Most users require m4 as a dependency of GNU autoconf. History Macro processors became popular when programmers commonly used assembly language. In those early days of programming, programmers noted that much of their programs consisted of repeated text, and they invented simple means for reusing this tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ragel
Ragel is a finite-state machine compiler and a parser generator. Initially Ragel supported output for C, C++ and Assembly source code, and was 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 state machin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BRL-CAD
BRL-CAD is a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system. It includes an interactive geometry editor, ray tracing support for graphics rendering and geometric analysis, computer network distributed framebuffer support, scripting, image-processing and signal-processing tools. The entire package is distributed in source code and binary form. Although BRL-CAD can be used for a variety of engineering and graphics applications, the package's primary purpose continues to be the support of ballistic and electromagnetic analyses. In keeping with the Unix philosophy of developing independent tools to perform single, specific tasks and then linking the tools together in a package, BRL-CAD is basically a collection of libraries, tools, and utilities that work together to create, raytrace, and interrogate geometry and manipulate files and data. In contrast to many other 3D modelling applications, BRL-CAD primarily uses CSG rather than boundary repres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Re2c
re2c is a free and open-source lexer generator for C, C++, Go, and Rust. 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 to debug and understand. Moreover, this approach often r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Leak
In computer science, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations in a way that Computer memory, memory which is no longer needed is not released. A memory leak may also happen when an object (computer science), object is stored in memory but cannot be accessed by the running code (i.e. unreachable memory). A memory leak has symptoms similar to a number of other problems and generally can only be diagnosed by a programmer with access to the program's source code. A related concept is the "space leak", which is when a program consumes excessive memory but does eventually release it. Because they can exhaust available system memory as an application runs, memory leaks are often the cause of or a contributing factor to software aging. Consequences A memory leak reduces the performance of the computer by reducing the amount of available memory. Eventually, in the worst case, too much of the available memory may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parser
Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Latin ''pars'' (''orationis''), meaning part (of speech). The term has slightly different meanings in different branches of linguistics and computer science. Traditional sentence parsing is often performed as a method of understanding the exact meaning of a sentence or word, sometimes with the aid of devices such as sentence diagrams. It usually emphasizes the importance of grammatical divisions such as subject and predicate. Within computational linguistics the term is used to refer to the formal analysis by a computer of a sentence or other string of words into its constituents, resulting in a parse tree showing their syntactic relation to each other, which may also contain semantic and other information (p-values). Some parsing algor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread Safety
Thread safety is a computer programming concept applicable to multi-threaded code. Thread-safe code only manipulates shared data structures in a manner that ensures that all threads behave properly and fulfill their design specifications without unintended interaction. There are various strategies for making thread-safe data structures. A program may execute code in several threads simultaneously in a shared address space where each of those threads has access to virtually all of the memory of every other thread. Thread safety is a property that allows code to run in multithreaded environments by re-establishing some of the correspondences between the actual flow of control and the text of the program, by means of synchronization. Levels of thread safety Software libraries can provide certain thread-safety guarantees. For example, concurrent reads might be guaranteed to be thread-safe, but concurrent writes might not be. Whether a program using such a library is thread-safe depends ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yacc
Yacc (Yet Another Compiler-Compiler) is a computer program for the Unix operating system developed by Stephen C. Johnson. It is a Look Ahead Left-to-Right Rightmost Derivation (LALR) parser generator, generating a LALR parser (the part of a compiler that tries to make syntactic sense of the source code) based on a formal grammar, written in a notation similar to Backus–Naur Form (BNF). Yacc is supplied as a standard utility on BSD and AT&T Unix. GNU-based Linux distributions include Bison, a forward-compatible Yacc replacement. History In the early 1970s, Stephen C. Johnson, a computer scientist at Bell Labs / AT&T, developed Yacc because he wanted to insert an exclusive or operator into a B language compiler (developed using McIlroy's TMG compiler-compiler), but it turned out to be a hard task. As a result, he was directed by his colleague at Bell Labs Al Aho to Donald Knuth's work on LR parsing, which served as the basis for Yacc. Yacc was influenced by and received ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced like the letter c'') is a General-purpose language, general-purpose computer programming language. It was created in the 1970s by Dennis Ritchie, and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted CPUs. It has found lasting use in operating systems, device drivers, protocol stacks, though decreasingly for application software. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the measuring programming language popularity, most widely used programming languages, with C compilers avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Bison
GNU Bison, commonly known as Bison, is a parser generator that is part of the GNU Project. Bison reads a specification in the BNF notation (a context-free language), warns about any parsing ambiguities, and generates a parser that reads sequences of tokens and decides whether the sequence conforms to the syntax specified by the grammar. The generated parsers are portable: they do not require any specific compilers. Bison by default generates LALR(1) parsers but it can also generate canonical LR, IELR(1) and GLR parsers. In POSIX mode, Bison is compatible with Yacc, but also has several extensions over this earlier program, including * Generation of counterexamples for conflicts * Location tracking (e.g., file, line, column) * Rich and internationalizable syntax error messages in the generated parsers * Customizable syntax error generation, * Reentrant parsers * Push parsers, with autocompletion * Support for named references * Several types of reports (graphical, XML) on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
