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Meta-II
META II is a domain-specific programming language for writing compilers. It was created in 1963–1964 by Dewey Val Schorre at UCLA. META II uses what Schorre called syntax equations. Its operation is simply explained as: Each ''syntax equation'' is translated into a recursive subroutine which tests the input string for a particular phrase structure, and deletes it if found. Meta II programs are compiled into an interpreted byte code language. VALGOL and SMALGOL compilers illustrating its capabilities were written in the META II language, VALGOL is a simple algebraic language designed for the purpose of illustrating META II. SMALGOL was a fairly large subset of ALGOL 60. Notation META II was first written in META I, a hand-compiled version of META II. The history is unclear as to whether META I was a full implementation of META II or a required subset of the META II language required to compile the full META II compiler. In its documentation, META II is described as resemblin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domain-specific Language
A domain-specific language (DSL) is a computer language specialized to a particular application domain. This is in contrast to a general-purpose language (GPL), which is broadly applicable across domains. There are a wide variety of DSLs, ranging from widely used languages for common domains, such as HTML for web pages, down to languages used by only one or a few pieces of software, such as MUSH soft code. DSLs can be further subdivided by the kind of language, and include domain-specific ''markup'' languages, domain-specific ''modeling'' languages (more generally, specification languages), and domain-specific ''programming'' languages. Special-purpose computer languages have always existed in the computer age, but the term "domain-specific language" has become more popular due to the rise of domain-specific modeling. Simpler DSLs, particularly ones used by a single application, are sometimes informally called mini-languages. The line between general-purpose languages and do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associativity
In mathematics, the associative property is a property of some binary operations, which means that rearranging the parentheses in an expression will not change the result. In propositional logic, associativity is a valid rule of replacement for expressions in logical proofs. Within an expression containing two or more occurrences in a row of the same associative operator, the order in which the operations are performed does not matter as long as the sequence of the operands is not changed. That is (after rewriting the expression with parentheses and in infix notation if necessary), rearranging the parentheses in such an expression will not change its value. Consider the following equations: \begin (2 + 3) + 4 &= 2 + (3 + 4) = 9 \,\\ 2 \times (3 \times 4) &= (2 \times 3) \times 4 = 24 . \end Even though the parentheses were rearranged on each line, the values of the expressions were not altered. Since this holds true when performing addition and multiplication on any rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1960s Software
Year 196 ( CXCVI) was a leap year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Dexter and Messalla (or, less frequently, year 949 ''Ab urbe condita''). The denomination 196 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Emperor Septimius Severus attempts to assassinate Clodius Albinus but fails, causing Albinus to retaliate militarily. * Emperor Septimius Severus captures and sacks Byzantium; the city is rebuilt and regains its previous prosperity. * In order to assure the support of the Roman legion in Germany on his march to Rome, Clodius Albinus is declared Augustus by his army while crossing Gaul. * Hadrian's wall in Britain is partially destroyed. China * First year of the '' Jian'an era of the Chinese Han Dynasty. * Emperor Xian of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OMeta
OMeta is a specialized object-oriented programming language for pattern matching, developed by Alessandro Warth and Ian Piumarta in 2007 under the Viewpoints Research Institute. The language is based on Parsing Expression Grammars (PEGs) rather than Context-Free Grammars with the intent of providing "a natural and convenient way for programmers to implement tokenizers, parsers, visitors, and tree-transformers".Warth, Alessandro, and Ian Piumarta.OMeta: An Object-Oriented Language for Pattern Matching" ACM SIGPLAN 2007 Dynamic Languages Symposium (DLS '07). 03rd ed. Vol. TR-2007. Glendale, CA: Viewpoints Research Institute, 2007. VPRI Technical Report. Web. 30 Sept. 2013. OMeta's main goal is to allow a broader audience to use techniques generally available only to language programmers, such as parsing. It is also known for its use in quickly creating prototypes, though programs written in OMeta are noted to be generally less efficient than those written in vanilla (base language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LISP 2
LISP 2 was a programming language proposed in the 1960s as the successor to Lisp. It had largely Lisp-like semantics and Algol 60-like syntax. Today it is mostly remembered for its syntax, but in fact it had many features beyond those of early Lisps. Early Lisps had many limitations, including limited data types and slow numerics. Its use of fully parenthesized notation was also considered a problem. The inventor of Lisp, John McCarthy, expected these issues to be addressed in a later version, called notionally Lisp 2. Hence the name Lisp 1.5 for the successor to the earliest Lisp.McCarthy, 1979 Lisp 2 was a joint project of the System Development Corporation and Information International, Inc., and was intended for the IBM built AN/FSQ-32 military computer. Development later shifted to the IBM 360/67 and the Digital Equipment Corporation PDP-6 The PDP-6, short for Programmed Data Processor model 6, is a computer developed by Digital Equipment Corporation (DEC) during 196 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Development Corporation
System Development Corporation (SDC) was a computer software company based in Santa Monica, California. Founded in 1955, it is considered the first company of its kind. History SDC began as the systems engineering group for the SAGE air-defense system at the RAND Corporation. In April 1955, the government contracted with RAND to help write software for the SAGE project. Within a few months, RAND's System Development Division had 500 employees developing SAGE applications. Within a year, the division had up to 1,000 employees. RAND spun off the group in 1957 as a non-profit organization that provided expertise for the United States military in the design, integration, and testing of large, complex, computer-controlled systems. SDC became a for-profit corporation in 1969, and began to offer its services to all organizations rather than only to the American military. The first two systems that SDC produced were the SAGE system, written for the IBM AN/FSQ-7 -7computer, and the SA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination. Virtual machines differ and are organized by their function, shown here: * '' System virtual machines'' (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs. * Process virtual machines are designed to execute computer programs in a platform-independent environment. Some virtual machine emulators, such as QEMU a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacompiler
In computer science, a compiler-compiler or compiler generator is a programming tool that creates a parser, interpreter, or compiler from some form of formal description of a programming language and machine. The most common type of compiler-compiler is more precisely called a parser generator. It only handles syntactic analysis. The input of a parser generator is a grammar file, typically written in Backus–Naur form (BNF) or extended Backus–Naur form (EBNF) that defines the syntax of a target programming language. The output is the source code of a parser for the programming language. The output of the (compiled) parser source code is a parser. It may be either standalone or embedded. This parser takes as an input the source code of the target programming language source and performs some action or outputs an abstract syntax tree (AST). Parser generators do not handle the semantics of the AST, or the generation of machine code for the target machine."A Syntax Directe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Polish Notation
Reverse Polish notation (RPN), also known as reverse Łukasiewicz notation, Polish postfix notation or simply postfix notation, is a mathematical notation in which operators ''follow'' their operands, in contrast to Polish notation (PN), in which operators ''precede'' their operands. It does not need any parentheses as long as each operator has a fixed number of operands. The description "Polish" refers to the nationality of logician Jan Łukasiewicz, who invented Polish notation in 1924. The first computer to use postfix notation, though it long remained essentially unknown outside of Germany, was Konrad Zuse's Z3 in 1941 as well as his Z4 in 1945. The reverse Polish scheme was again proposed in 1954 by Arthur Burks, Don Warren, and Jesse Wright and was independently reinvented by Friedrich L. Bauer and Edsger W. Dijkstra in the early 1960s to reduce computer memory access and use the stack to evaluate expressions. The algorithms and notation for this scheme were extended ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recursive Descent
In computer science, a recursive descent parser is a kind of top-down parsing, top-down parser built from a set of mutual recursion, mutually recursive procedures (or a non-recursive equivalent) where each such procedure (computer science), procedure implements one of the Terminal and nonterminal symbols, nonterminals of the formal grammar, grammar. Thus the structure of the resulting program closely mirrors that of the grammar it recognizes. A ''predictive parser'' is a recursive descent parser that does not require backtracking. Predictive parsing is possible only for the class of LL parser, LL(''k'') grammars, which are the context-free grammars for which there exists some positive integer ''k'' that allows a recursive descent parser to decide which production to use by examining only the next ''k'' tokens of input. The LL(''k'') grammars therefore exclude all ambiguous grammars, as well as all grammars that contain left recursion. Any context-free grammar can be transformed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning), which are usually defined by a formal language. Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard) while other languages (such as Perl) have a dominant Programming language implementation, implementation that is treated as a reference implementation, reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common. Programming language theory is the subfield of computer science that studies the design, implementation, analysis, characterization, and classification of programming lan ... [...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 alg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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