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Duck Typing
Duck typing in computer programming is an application of the duck test—"If it walks like a duck and it quacks like a duck, then it must be a duck"—to determine whether an object can be used for a particular purpose. With nominative typing, an object is ''of a given type'' if it is declared to be (or if a type's association with the object is inferred through mechanisms such as object inheritance). In duck typing, an object is ''of a given type'' if it has all methods and properties required by that type. Duck typing can be viewed as a usage-based structural equivalence between a given object and the requirements of a type. See structural typing for a further explanation of structural type equivalence. Example This is a simple example in Python 3 that demonstrates how any object may be used in any context, up until it is used in a way that it does not support. class Duck: def swim(self): print("Duck swimming") def fly(self): print("Duck flyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duck Test
The duck test is a form of abductive reasoning, usually expressed as "If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck." The test implies that a person can identify an unknown subject by observing that subject's habitual characteristics. It is sometimes used to counter abstruse arguments that something is not what it appears to be. History The French automaton maker Jacques de Vaucanson created a mechanical duck in 1738. The mechanical duck would quack, move its head to eat grain which it would appear to digest, and after a short time would excrete a mixture that looked and smelled like duck droppings. The irony is that while the phrase is often cited as proof of abductive reasoning, it is not proof, as the mechanical duck is still not a living duck. In popular culture Douglas Adams parodied this test in his book ''Dirk Gently's Holistic Detective Agency'': Monty Python also referenced the test in the Witch Logic scene i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adapter Pattern
In software engineering, the adapter pattern is a software design pattern (also known as wrapper, an alternative naming shared with the decorator pattern) that allows the interface of an existing class to be used as another interface. It is often used to make existing classes work with others without modifying their source code. An example is an adapter that converts the interface of a Document Object Model of an XML document into a tree structure that can be displayed. Overview The adapter design pattern is one of the twenty-three well-known Gang of Four design patterns that describe how to solve recurring design problems to design flexible and reusable object-oriented software, that is, objects that are easier to implement, change, test, and reuse. The adapter design pattern solves problems like: * How can a class be reused that does not have an interface that a client requires? * How can classes that have incompatible interfaces work together? * How can an alternative interfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Programming
Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of procedures (often known as ''methods''). A common feature of objects is that procedures (or methods) are attached to them and can access and modify the object's data fields. In this brand of OOP, there is usually a special name such as or used to refer to the current object. In OOP, computer programs are designed by making them out of objects that interact with one another. OOP languages are diverse, but the most popular ones are class-based, meaning that objects are instances of classes, which also determine their types. Many of the most widely used programming languages (such as C++, Java, Python, etc.) are multi-paradigm and they support object-oriented programming to a greater or lesser degree, typically in combination with imper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Articles With Example Pseudocode
Article often refers to: * Article (grammar), a grammatical element used to indicate definiteness or indefiniteness * Article (publishing), a piece of nonfictional prose that is an independent part of a publication Article may also refer to: Government and law * Article (European Union), articles of treaties of the European Union * Articles of association, the regulations governing a company, used in India, the UK and other countries * Articles of clerkship, the contract accepted to become an articled clerk * Articles of Confederation, the predecessor to the current United States Constitution *Article of Impeachment, a formal document and charge used for impeachment in the United States * Articles of incorporation, for corporations, U.S. equivalent of articles of association * Articles of organization, for limited liability organizations, a U.S. equivalent of articles of association Other uses * Article, an HTML element, delimited by the tags and * Article of clothing, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Programming Language
In computer science, a dynamic programming language is a class of high-level programming languages, which at runtime execute many common programming behaviours that static programming languages perform during compilation. These behaviors could include an extension of the program, by adding new code, by extending objects and definitions, or by modifying the type system. Although similar behaviors can be emulated in nearly any language, with varying degrees of difficulty, complexity and performance costs, dynamic languages provide direct tools to make use of them. Many of these features were first implemented as native features in the Lisp programming language. Most dynamic languages are also dynamically typed, but not all are. Dynamic languages are frequently (but not always) referred to as scripting languages, although that term in its narrowest sense refers to languages specific to a given run-time environment. Implementation Eval Some dynamic languages offer an ''eval'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monkey Patch
Monkey patching is a technique used to dynamically update the behavior of a piece of code at run-time. A monkey patch (also spelled monkey-patch, MonkeyPatch) is a way to extend or modify the runtime code of dynamic languages (e.g. Smalltalk, JavaScript, Objective-C, Ruby, Perl, Python, Groovy, etc.) without altering the original source code. Etymology The term ''monkey patch'' seems to have come from an earlier term, ''guerrilla patch'', which referred to changing code sneakily – and possibly incompatibly with other such patches – at runtime. The word '' guerrilla'', nearly homophonous with ''gorilla'', became ''monkey'', possibly to make the patch sound less intimidating. An alternative etymology is that it refers to “monkeying about” with the code (messing with it). Despite the name's suggestion, the "monkey patch" is sometimes the official method of extending a program. For example, web browsers such as Firefox and Internet Explorer used to encourage this, although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loose Coupling
In computing and systems design, a loosely coupled system is one # in which components are weakly associated (have breakable relationships) with each other, and thus changes in one component least affect existence or performance of another component. # in which each of its components has, or makes use of, little or no knowledge of the definitions of other separate components. Subareas include the coupling of classes, interfaces, data, and services. Loose coupling is the opposite of tight coupling. Advantages and disadvantages Components in a loosely coupled system can be replaced with alternative implementations that provide the same services. Components in a loosely coupled system are less constrained to the same platform, language, operating system, or build environment. If systems are decoupled in time, it is difficult to also provide transactional integrity; additional coordination protocols are required. Data replication across different systems provides loose coupling (i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UFCS
Uniform Function Call Syntax (UFCS) or Uniform Calling Syntax (UCS) or sometimes Universal Function Call Syntax is a programming language feature in D and Nim that allows any function to be called using the syntax for method calls (as in object-oriented programming), by using the receiver as the first parameter, and the given arguments as the remaining parameters. UFCS is particularly useful when function calls are chained (behaving similar to pipes, or the various dedicated operators available in functional languages for passing values through a series of expressions). It allows free-functions to fill a role similar to extension methods in some other languages. Another benefit of the method call syntax is use with " dot-autocomplete" in IDEs, which use type information to show a list of available functions, dependent on the context. When the programmer starts with an argument, the set of potentially applicable functions is greatly narrowed down, aiding discoverability. Exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extension Method
In object-oriented computer programming, an extension method is a method added to an object after the original object was compiled. The modified object is often a class, a prototype or a type. Extension methods are features of some object-oriented programming languages. There is no syntactic difference between calling an extension method and calling a method declared in the type definition. Not all languages implement extension methods in an equally safe manner, however. For instance, languages such as C#, Java (viManifoldoLombok, and Kotlin don't alter the extended class in any way, because doing so may break class hierarchies and interfere with virtual method dispatching. This is why these languages strictly implement extension methods statically and use static dispatching to invoke them. Support in programming languages Extension methods are features of numerous languages including C#, Java viManifoldoLombok Gosu, JavaScript, Oxygene, Ruby, Smalltalk, Kotlin, Dart, Vis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java (programming Language)
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywhere'' ( WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. , Java was one of the most popular programming languages in use according to GitHub, particularly for client–server web applications, with a reported 9 million developers. Java was originally developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection (computer Programming)
In computer science, reflective programming or reflection is the ability of a process to examine, introspect, and modify its own structure and behavior. Historical background The earliest computers were programmed in their native assembly languages, which were inherently reflective, as these original architectures could be programmed by defining instructions as data and using self-modifying code. As the bulk of programming moved to higher-level compiled languages such as Algol, Cobol, Fortran, Pascal, and C, this reflective ability largely disappeared until new programming languages with reflection built into their type systems appeared. Brian Cantwell Smith's 1982 doctoral dissertation introduced the notion of computational reflection in procedural programming languages and the notion of the meta-circular interpreter as a component of 3-Lisp. Uses Reflection helps programmers make generic software libraries to display data, process different formats of data, perform serial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unreachable Code
In computer programming, unreachable code is part of the source code of a program which can never be executed because there exists no control flow path to the code from the rest of the program. Unreachable code is sometimes also called ''dead code'', although dead code may also refer to code that is executed but has no effect on the output of a program. Unreachable code is generally considered undesirable for several reasons: * It uses memory unnecessarily * It can cause unnecessary use of the CPU's instruction cache ** This can also decrease data locality * Time and effort may be spent testing, maintaining and documenting code which is never used ** Sometimes an automated test is the only thing using the code. However, unreachable code can have some legitimate uses, like providing a library of functions for calling or jumping to manually via a debugger while the program is halted after a breakpoint. This is particularly useful for examining and pretty-printing the internal state ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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