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Funarg Problem
In computer science, the funarg problem ''(function argument problem)'' refers to the difficulty in implementing first-class functions (functions as first-class objects) in programming language implementations so as to use stack-based memory allocation of the functions. The difficulty only arises if the body of a nested function refers directly (i.e., not by argument passing) to identifiers defined in the environment in which the function is defined, but not in the environment of the function call. A standard resolution is either to forbid such references or to create closures. There are two subtly different versions of the funarg problem. The upwards funarg problem arises from returning (or otherwise transmitting "upwards") a function from a function call. The downwards funarg problem arises from passing a function as a parameter to another function call. Upwards funarg problem When one function calls another during a typical program's execution, the local state of the caller (in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ML (programming Language)
ML (Meta Language) is a general-purpose, high-level, functional programming language. It is known for its use of the polymorphic Hindley–Milner type system, which automatically assigns the data types of most expressions without requiring explicit type annotations ( type inference), and ensures type safety; there is a formal proof that a well-typed ML program does not cause runtime type errors. ML provides pattern matching for function arguments, garbage collection, imperative programming, call-by-value and currying. While a general-purpose programming language, ML is used heavily in programming language research and is one of the few languages to be completely specified and verified using formal semantics. Its types and pattern matching make it well-suited and commonly used to operate on other formal languages, such as in compiler writing, automated theorem proving, and formal verification. Overview Features of ML include a call-by-value evaluation strategy, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple, Inc
Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Computer Company by Steve Jobs, Steve Wozniak and Ronald Wayne, the company was incorporated by Jobs and Wozniak as Apple Computer, Inc. the following year. It was renamed Apple Inc. in 2007 as the company had expanded its focus from computers to consumer electronics. Apple is the largest technology company by revenue, with billion in the 2024 fiscal year. The company was founded to produce and market Wozniak's Apple I personal computer. Its second computer, the Apple II, became a best seller as one of the first mass-produced microcomputers. Apple introduced the Lisa in 1983 and the Macintosh in 1984, as some of the first computers to use a graphical user interface and a computer mouse, mouse. By 1985, internal company problems led to Job ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced'' '' – like the letter c'') is a general-purpose 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 Central processing unit, CPUs. It has found lasting use in operating systems code (especially in Kernel (operating system), kernels), device drivers, and protocol stacks, but its use in application software has been decreasing. 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 most widely used programming langu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oberon (programming Language)
Oberon is a general-purpose programming language first published in 1987 by Niklaus Wirth and the latest member of the Wirthian family of ALGOL-like languages ( Euler, ALGOL W, Pascal, Modula, and Modula-2). Oberon was the result of a concentrated effort to increase the power of Modula-2, the direct successor of Pascal, and simultaneously to reduce its complexity. Its principal new feature is the concept of data type extension of record types. It permits constructing new data types on the basis of existing ones and to relate them, deviating from the dogma of strict static typing of data. Type extension is Wirth's way of inheritance reflecting the viewpoint of the parent site. Oberon was developed as part of the implementation of an operating system, also named Oberon at ETH Zurich in Switzerland. The name was inspired both by the Voyager space probe's pictures of the moon of the planet Uranus, named Oberon, and because Oberon is famous as the king of the elves. Obero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modula-2
Modula-2 is a structured, procedural programming language developed between 1977 and 1985/8 by Niklaus Wirth at ETH Zurich. It was created as the language for the operating system and application software of the Lilith personal workstation. It was later used for programming outside the context of the Lilith. Wirth viewed Modula-2 as a successor to his earlier programming languages Pascal and Modula. The main concepts are: # The module as a compiling unit for separate compiling # The coroutine as the basic building block for concurrent processes # Types and procedures that allow access to machine-specific data The language design was influenced by the Mesa language and the Xerox Alto, both from Xerox PARC, that Wirth saw during his 1976 sabbatical year there. Page 4. The computer magazine ''Byte'' devoted the August 1984 issue to the language and its surrounding environment. Wirth created the Oberon series of languages as the successor to Modula-2, while others (particularl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal Programming Language
Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named after French mathematician, philosopher and physicist Blaise Pascal. Pascal was developed on the pattern of the ALGOL 60 language. Wirth was involved in the process to improve the language as part of the ALGOL X efforts and proposed a version named ALGOL W. This was not accepted, and the ALGOL X process bogged down. In 1968, Wirth decided to abandon the ALGOL X process and further improve ALGOL W, releasing this as Pascal in 1970. On top of ALGOL's scalars and arrays, Pascal enables defining complex datatypes and building dynamic and recursive data structures such as lists, trees and graphs. Pascal has strong typing on all objects, which means that one type of data cannot be converted to or interpreted as another without explicit conversions. Unlike ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuation-passing Style
In functional programming, continuation-passing style (CPS) is a style of programming in which control is passed explicitly in the form of a continuation. This is contrasted with direct style, which is the usual style of programming. Gerald Jay Sussman and Guy L. Steele, Jr. coined the phrase in AI Memo 349 (1975), which sets out the first version of the programming language Scheme. John C. Reynolds gives a detailed account of the many discoveries of continuations. A function written in continuation-passing style takes an extra argument: an explicit ''continuation''; i.e., a function of one argument. When the CPS function has computed its result value, it "returns" it by calling the continuation function with this value as the argument. That means that when invoking a CPS function, the calling function is required to supply a procedure to be invoked with the subroutine's "return" value. Expressing code in this form makes a number of things explicit which are implicit in direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tail Call
In computer science, a tail call is a subroutine call performed as the final action of a procedure. If the target of a tail is the same subroutine, the subroutine is said to be tail recursive, which is a special case of direct recursion. Tail recursion (or tail-end recursion) is particularly useful, and is often easy to optimize in implementations. Tail calls can be implemented without adding a new stack frame to the call stack. Most of the frame of the current procedure is no longer needed, and can be replaced by the frame of the tail call, modified as appropriate (similar to overlay for processes, but for function calls). The program can then jump to the called subroutine. Producing such code instead of a standard call sequence is called tail-call elimination or tail-call optimization. Tail-call elimination allows procedure calls in tail position to be implemented as efficiently as goto statements, thus allowing efficient structured programming. In the words of Guy L. Steele, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Calculus
In mathematical logic, the lambda calculus (also written as ''λ''-calculus) is a formal system for expressing computability, computation based on function Abstraction (computer science), abstraction and function application, application using variable Name binding, binding and Substitution (algebra), substitution. Untyped lambda calculus, the topic of this article, is a universal machine, a model of computation that can be used to simulate any Turing machine (and vice versa). It was introduced by the mathematician Alonzo Church in the 1930s as part of his research into the foundations of mathematics. In 1936, Church found a formulation which was #History, logically consistent, and documented it in 1940. Lambda calculus consists of constructing #Lambda terms, lambda terms and performing #Reduction, reduction operations on them. A term is defined as any valid lambda calculus expression. In the simplest form of lambda calculus, terms are built using only the following rules: # x: A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Function Composition (computer Science)
In computer science, function composition is an act or mechanism to combine simple functions to build more complicated ones. Like the usual composition of functions in mathematics, the result of each function is passed as the argument of the next, and the result of the last one is the result of the whole. Programmers frequently apply functions to results of other functions, and almost all programming languages allow it. In some cases, the composition of functions is interesting as a function in its own right, to be used later. Such a function can always be defined but languages with first-class functions make it easier. The ability to easily compose functions encourages factoring (breaking apart) functions for maintainability and code reuse. More generally, big systems might be built by composing whole programs. Narrowly speaking, function composition applies to functions that operate on a finite amount of data, each step sequentially processing it before handing it to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudocode
In computer science, pseudocode is a description of the steps in an algorithm using a mix of conventions of programming languages (like assignment operator, conditional operator, loop) with informal, usually self-explanatory, notation of actions and conditions. Although pseudocode shares features with regular programming languages, it is intended for human reading rather than machine control. Pseudocode typically omits details that are essential for machine implementation of the algorithm, meaning that pseudocode can only be verified by hand. The programming language is augmented with natural language description details, where convenient, or with compact mathematical notation. The reasons for using pseudocode are that it is easier for people to understand than conventional programming language code and that it is an efficient and environment-independent description of the key principles of an algorithm. It is commonly used in textbooks and scientific publications to document ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
