|
Void Safety
Void safety (also known as null safety) is a guarantee within an object-oriented programming language that no object references will have ''null'' or ''void'' values. In object-oriented languages, access to objects is achieved through references (or, equivalently, pointers). A typical call is of the form: x.f(a, ...) where ''f'' denotes an operation and ''x'' denotes a reference to some object. At execution time, however, a reference can be ''void'' (or ''null''). In such cases, the call above will be a void call, leading to a run-time exception, often resulting in abnormal termination of the program. Void safety is a static (compile-time) guarantee that a void call will never arise. History In a 2009 talk, Tony Hoare traced the invention of the null pointer to his design of the ALGOL W language and called it a "mistake": Bertrand Meyer introduced the term "void safety". In programming languages An early attempt to guarantee void safety was the design of the Self program ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Language
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 impera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Union Type
In computer science, a union is a value that may have any of several representations or formats within the same position in memory; that consists of a variable that may hold such a data structure. Some programming languages support special data types, called union types, to describe such values and variables. In other words, a union type definition will specify which of a number of permitted primitive types may be stored in its instances, e.g., "float or long integer". In contrast with a record (or structure), which could be defined to contain both a float ''and'' an integer; in a union, there is only one value at any given time. A union can be pictured as a chunk of memory that is used to store variables of different data types. Once a new value is assigned to a field, the existing data is overwritten with the new data. The memory area storing the value has no intrinsic type (other than just bytes or words of memory), but the value can be treated as one of several abstract data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Option Type
In programming languages (especially functional programming languages) and type theory, an option type or maybe type is a polymorphic type that represents encapsulation of an optional value; e.g., it is used as the return type of functions which may or may not return a meaningful value when they are applied. It consists of a constructor which either is empty (often named None or Nothing), or which encapsulates the original data type A (often written Just A or Some A). A distinct, but related concept outside of functional programming, which is popular in object-oriented programming, is called nullable types (often expressed as A?). The core difference between option types and nullable types is that option types support nesting (e.g. Maybe (Maybe String) ≠ Maybe String), while nullable types do not (e.g. String?? = String?). Theoretical aspects In type theory, it may be written as: A^ = A + 1. This expresses the fact that for a given set of values in A, an option type adds ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nullable Type
Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type. In statically typed languages, a nullable type is an option type, while in dynamically typed languages (where values have types, but variables do not), equivalent behavior is provided by having a single null value. NULL is frequently used to represent a missing value or invalid value, such as from a function that failed to return or a missing field in a database, as in NULL in SQL. In other words NULL is undefined. Primitive types such as integers and Booleans cannot generally be null, but the corresponding nullable types (nullable integer and nullable Boolean, respectively) can also assume the NULL value. This can be represented in ternary logic as FALSE,NULL,TRUE as in three-valued logic. Example An integer variable may represent integers, but 0 (zero) is a special case because 0 in many programming language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swift (programming Language)
Swift is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. and the open-source community. First released in 2014, Swift was developed as a replacement for Apple's earlier programming language Objective-C, as Objective-C had been largely unchanged since the early 1980s and lacked modern language features. Swift works with Apple's Cocoa and Cocoa Touch frameworks, and a key aspect of Swift's design was the ability to interoperate with the huge body of existing Objective-C code developed for Apple products over the previous decades. It was built with the open source LLVM compiler framework and has been included in Xcode since version 6, released in 2014. On Apple platforms, it uses the Objective-C runtime library, which allows C, Objective-C, C++ and Swift code to run within one program. Apple intended Swift to support many core concepts associated with Objective-C, notably dynamic dispatch, widespread late binding, extensible programming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rust (programming Language)
Rust is a multi-paradigm, general-purpose programming language. Rust emphasizes performance, type safety, and concurrency. Rust enforces memory safety—that is, that all references point to valid memory—without requiring the use of a garbage collector or reference counting present in other memory-safe languages. To simultaneously enforce memory safety and prevent concurrent data races, Rust's "borrow checker" tracks the object lifetime of all references in a program during compilation. Rust is popular for systems programming but also offers high-level features including some functional programming constructs. Software developer Graydon Hoare created Rust as a personal project while working at Mozilla Research in 2006. Mozilla officially sponsored the project in 2009. Since the first stable release in May 2015, Rust has been adopted by companies including Amazon, Discord, Dropbox, Facebook ( Meta), Google (Alphabet), and Microsoft. Rust has been noted for its growth as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kotlin (programming Language)
Kotlin () is a cross-platform software, cross-platform, static typing, statically typed, general-purpose programming language, general-purpose programming language with type inference. Kotlin is designed to interoperate fully with Java (programming language), Java, and the Java virtual machine, JVM version of Kotlin's standard library depends on the Java Class Library, but type inference allows its syntax (programming languages), syntax to be more concise. Kotlin mainly targets the JVM, but also compiles to JavaScript (e.g., for frontend web applications using React (web framework), React) or machine code, native code via LLVM (e.g., for native iOS apps sharing business logic with Android (operating system), Android apps). Language development costs are borne by JetBrains, while the Kotlin Foundation protects the Kotlin trademark. On 7 May 2019, Google announced that the Kotlin programming language is now its preferred language for Android (operating system), Android app develop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dart (programming Language)
Dart is a programming language designed for client development, such as for the web and mobile apps. It is developed by Google and can also be used to build server and desktop applications. It is an object-oriented, class-based, garbage-collected language with C-style syntax. It can compile to either machine code or JavaScript, and supports interfaces, mixins, abstract classes, reified generics and type inference. History Dart was unveiled at the GOTO conference in Aarhus, Denmark, October 10–12, 2011. The project was founded by Lars Bak and Kasper Lund. Dart 1.0 was released on November 14, 2013. Dart initially had a mixed reception and the Dart initiative has been criticized by some for fragmenting the web, due to the original plans to include a Dart VM in Chrome. Those plans were dropped in 2015 with the 1.9 release of Dart to focus instead on compiling Dart to JavaScript. Dart 2.0 was released in August 2018, with language changes including a type system. Dart 2.6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Sharp (programming Language)
C# (pronounced ) is a general-purpose, high-level multi-paradigm programming language. C# encompasses static typing, strong typing, lexically scoped, imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines. The C# programming language was designed by Anders Hejlsberg from Microsoft in 2000 and was later approved as an international standard by Ecma (ECMA-334) in 2002 and ISO/IEC (ISO/IEC 23270) in 2003. Microsoft introduced C# along with .NET Framework and Visual Studio, both of which were closed-source. At the time, Microsoft had no open-source products. Four years later, in 2004, a free and open-source project called Mono began, providing a cross-platform compiler and runtime environment for the C# programming language. A decade later, Microsoft released Visual Studio Code (code editor), Roslyn (compiler), and the unified .NET platform (software framework), all of which support C# and are free, open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TypeScript
TypeScript is a free and open source 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 ... developed and maintained by Microsoft. It is a strict syntactical superset of JavaScript and adds optional static typing to the language. It is designed for the development of large applications and source-to-source compiler, transpiles to JavaScript. As it is a superset of JavaScript, existing JavaScript programs are also valid TypeScript programs. TypeScript may be used to develop JavaScript applications for both client-side and server-side execution (as with Node.js or Deno (software), Deno). Multiple options are available for transpilation. The default TypeScript Compiler can be used, or the Babel (transcompiler), Babel compiler can be invoked to convert TypeScript to J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceylon (programming Language)
Ceylon is an object-oriented, strongly statically typed programming language with an emphasis on immutability, created by Red Hat. Ceylon programs run on the Java virtual machine (JVM), and could be compiled to JavaScript. The language design focuses on source code readability, predictability, toolability, modularity, and metaprogrammability. Important features of Ceylon include: * A type system enforcing null safety and list element existence at compile time * Regular syntax and semantics, avoiding special cases and primitively-defined constructs in favor of syntactic sugar * Support for generic programming and metaprogramming, with reified generics * Modularity built into the language, based on JBoss modules, interoperable with OSGi and Maven * powerful tools, including an Eclipse-based IDE The name "Ceylon" is an oblique reference to Java, in that Java and Sri Lanka, formerly known as Ceylon, are islands known for growth and export of coffee and tea. In August 2017, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intersection Type
In type theory, an intersection type can be allocated to values that can be assigned both the type \sigma and the type \tau. This value can be given the intersection type \sigma \cap \tau in an intersection type system. Generally, if the ranges of values of two types overlap, then a value belonging to the ''intersection'' of the two ranges can be assigned the ''intersection type'' of these two types. Such a value can be safely passed as argument to functions expecting ''either'' of the two types. For example, in Java_(programming_language), Java the class implements both the and the interfaces. Therefore, an object of type can be safely passed to functions expecting an argument of type and to functions expecting an argument of type . Intersection types are composite data types. Similar to product types, they are used to assign several types to an object. However, product types are assigned to tuples, so that each tuple element is assigned a particular product type component. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
