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Homoiconic
In computer programming, homoiconicity (from the Greek words ''homo-'' meaning "the same" and ''icon'' meaning "representation") is a property of some programming languages. A language is homoiconic if a program written in it can be manipulated as data using the language, and thus the program's internal representation can be inferred just by reading the program itself. This property is often summarized by saying that the language treats "code as data". In a homoiconic language, the primary representation of programs is also a data structure in a primitive type of the language itself. This makes metaprogramming easier than in a language without this property: reflection in the language (examining the program's entities at runtime) depends on a single, homogeneous structure, and it does not have to handle several different structures that would appear in a complex syntax. Homoiconic languages typically include full support of syntactic macros, allowing the programmer to express tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red (programming Language)
Red is a programming language designed to overcome the limitations of the programming language Rebol. Red was introduced in 2011 by Nenad Rakočević, and is both an imperative and functional programming language. Its syntax and general usage overlaps that of the interpreted Rebol language. The implementation choices of Red intend to create a full stack programming language: Red can be used for extremely high-level programming (DSLs and GUIs) as well as low-level programming (operating systems and device drivers). Key to the approach is that the language has two parts: ''Red/System'' and ''Red''. * ''Red/System'' is similar to C, but packaged into a Rebol lexical structure for example, one would write instead of . * ''Red'' is a homoiconic language capable of meta-programming, with Rebol-like semantics. Red's runtime library is written in Red/System, and uses a hybrid approach: it compiles what it can deduce statically and uses an embedded interpreter otherwise. The project ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRAC (programming Language)
TRAC (for Text Reckoning And Compiling) Language is a programming language developed between 1959–1964 by Calvin Mooers and first implemented on the PDP-1 in 1964 by L. Peter Deutsch. It was one of three "first languages" recommended by Ted Nelson in ''Computer Lib''. TRAC T64 was used until at least 1984, when Mooers updated it to TRAC T84. Language description TRAC is a purely text-based language — a kind of macro language. Unlike traditional ''ad hoc'' macro languages of the time, such as those found in assemblers, TRAC is well planned, consistent, and in many senses complete. It has explicit input and output operators, unlike the typical implicit I/O at the outermost macro level, which makes it simultaneously simpler and more versatile than older macro languages. It also differs from traditional macro languages in that TRAC numbers are strings of digits, with integer arithmetic (without specific limits on maximum values) being provided through built-in ("primitive") func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clojure
Clojure (, like ''closure'') is a dynamic and functional dialect of the Lisp programming language on the Java platform. Like other Lisp dialects, Clojure treats code as data and has a Lisp macro system. The current development process is community-driven, overseen by Rich Hickey as its benevolent dictator for life (BDFL). Clojure advocates immutability and immutable data structures and encourages programmers to be explicit about managing identity and its states. This focus on programming with immutable values and explicit progression-of-time constructs is intended to facilitate developing more robust, especially concurrent, programs that are simple and fast. While its type system is entirely dynamic, recent efforts have also sought the implementation of a dependent type system. History and development process Rich Hickey is the creator of the Clojure language. Before Clojure, he developed dotLisp, a similar project based on the .NET platform, and three earlier attempts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prolog
Prolog is a logic programming language associated with artificial intelligence and computational linguistics. Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended primarily as a declarative programming language: the program logic is expressed in terms of relations, represented as facts and rules. A computation is initiated by running a ''query'' over these relations. The language was developed and implemented in Marseille, France, in 1972 by Alain Colmerauer with Philippe Roussel, based on Robert Kowalski's procedural interpretation of Horn clauses at University of Edinburgh. Prolog was one of the first logic programming languages and remains the most popular such language today, with several free and commercial implementations available. The language has been used for theorem proving, expert systems, term rewriting, type systems, and automated planning, as well as its original intended field of use, nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-expression
In computer programming, an S-expression (or symbolic expression, abbreviated as sexpr or sexp) is an expression in a like-named notation for nested list (tree-structured) data. S-expressions were invented for and popularized by the programming language Lisp, which uses them for source code as well as data. In the usual parenthesized syntax of Lisp, an S-expression is classically definedJohn McCarthy (1960/2006)Recursive functions of symbolic expressions. Originally published in Communications of the ACM. as # an atom of the form ''x'', or # an expression of the form (''x'' . ''y'') where ''x'' and ''y'' are S-expressions. This definition reflects LISP's representation of a list as a series of "cells", each one an ordered pair. In plain lists, ''y'' points to the next cell (if any), thus forming a list. The recursive clause of the definition means that both this representation and the S-expression notation can represent any binary tree. However, the representation can in princi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lisp (programming Language)
Lisp (historically LISP) is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in 1960, Lisp is the second-oldest high-level programming language still in common use, after Fortran. Lisp has changed since its early days, and many dialects have existed over its history. Today, the best-known general-purpose Lisp dialects are Common Lisp, Scheme, Racket and Clojure. Lisp was originally created as a practical mathematical notation for computer programs, influenced by (though not originally derived from) the notation of Alonzo Church's lambda calculus. It quickly became a favored programming language for artificial intelligence (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, conditionals, higher-order functions, recursion, the self-hosting compiler, and the read ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaprogramming
Metaprogramming is a programming technique in which computer programs have the ability to treat other programs as their data. It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself while running. In some cases, this allows programmers to minimize the number of lines of code to express a solution, in turn reducing development time. It also allows programs a greater flexibility to efficiently handle new situations without recompilation. Metaprogramming can be used to move computations from run-time to compile-time, to generate code using compile time computations, and to enable self-modifying code. The ability of a programming language to be its own metalanguage is called reflection. Reflection is a valuable language feature to facilitate metaprogramming. Metaprogramming was popular in the 1970s and 1980s using list processing languages such as LISP. LISP hardware machines were popular in the 1980s and enabled app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lisp Programming Language
Lisp (historically LISP) is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in 1960, Lisp is the second-oldest high-level programming language still in common use, after Fortran. Lisp has changed since its early days, and many dialects have existed over its history. Today, the best-known general-purpose Lisp dialects are Common Lisp, Scheme, Racket and Clojure. Lisp was originally created as a practical mathematical notation for computer programs, influenced by (though not originally derived from) the notation of Alonzo Church's lambda calculus. It quickly became a favored programming language for artificial intelligence (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, conditionals, higher-order functions, recursion, the self-hosting compiler, and the read ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheme (programming Language)
Scheme is a dialect of the Lisp family of programming languages. Scheme was created during the 1970s at the MIT AI Lab and released by its developers, Guy L. Steele and Gerald Jay Sussman, via a series of memos now known as the Lambda Papers. It was the first dialect of Lisp to choose lexical scope and the first to require implementations to perform tail-call optimization, giving stronger support for functional programming and associated techniques such as recursive algorithms. It was also one of the first programming languages to support first-class continuations. It had a significant influence on the effort that led to the development of Common Lisp.Common LISP: The Language, 2nd Ed., Guy L. Steele Jr. Digital Press; 1981. . "Common Lisp is a new dialect of Lisp, a successor to MacLisp, influenced strongly by ZetaLisp and to some extent by Scheme and InterLisp." The Scheme language is standardized in the official IEEE standard1178-1990 (Reaff 2008) IEEE Standard for the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Neumann Architecture
The von Neumann architecture — also known as the von Neumann model or Princeton architecture — is a computer architecture based on a 1945 description by John von Neumann, and by others, in the ''First Draft of a Report on the EDVAC''. The document describes a design architecture for an electronic digital computer with these components: * A processing unit with both an arithmetic logic unit and processor registers * A control unit that includes an instruction register and a program counter * Memory that stores data and instructions * External mass storage * Input and output mechanisms.. The term "von Neumann architecture" has evolved to refer to any stored-program computer in which an instruction fetch and a data operation cannot occur at the same time (since they share a common bus). This is referred to as the von Neumann bottleneck, which often limits the performance of the corresponding system. The design of a von Neumann architecture machine is simpler than in a Harva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meta-circular Evaluator
In computing, a meta-circular evaluator (MCE) or meta-circular interpreter (MCI) is an interpreter which defines each feature of the interpreted language using a similar facility of the interpreter's host language. For example, interpreting a lambda application may be implemented using function application. Meta-circular evaluation is most prominent in the context of Lisp. A self-interpreter is a meta-circular interpreter where the interpreted language is nearly identical to the host language; the two terms are often used synonymously. History The dissertation of Corrado Böhm describes the design of a self-hosting compiler. Due to the difficulty of compiling higher-order functions, many languages were instead defined via interpreters, most prominently Lisp. The term itself was coined by John C. Reynolds, and popularized through its use in the book ''Structure and Interpretation of Computer Programs''. Self-interpreters A self-interpreter is a meta-circular interpreter wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eval
In some programming languages, eval , short for the English evaluate, is a function which evaluates a string as though it were an expression in the language, and returns a result; in others, it executes multiple lines of code as though they had been included instead of the line including the eval. The input to eval is not necessarily a string; it may be structured representation of code, such as an abstract syntax tree (like Lisp forms), or of special type such as code (as in Python). The analog for a statement is exec, which executes a string (or code in other format) as if it were a statement; in some languages, such as Python, both are present, while in other languages only one of either eval or exec is. Eval and apply are instances of meta-circular evaluators, interpreters of a language that can be invoked within the language itself. Security risks Using eval with data from an untrusted source may introduce security vulnerabilities. For instance, assuming that the get_da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
