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Null Coalescing Operator
The null coalescing operator (called the Logical Defined-Or operator in Perl) is a binary operator that is part of the syntax for a basic conditional expression in several programming languages, including C#, PowerShell as of version 7.0.0, Perl as of version 5.10, Swift, and PHP 7.0.0. While its behavior differs between implementations, the null coalescing operator generally returns the result of its left-most operand if it exists and is not null, and otherwise returns the right-most operand. This behavior allows a default value to be defined for cases where a more specific value is not available. In contrast to the ternary conditional if operator used as x ? x : y, but like the binary Elvis operator used as x ?: y, the null coalescing operator is a binary operator and thus evaluates its operands at most once, which is significant if the evaluation of x has side-effects. Examples by languages Bourne-like Shells In Bourne shell (and derivatives), "If ''parameter'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was officially changed to Raku in October 2019. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Raku, which began as a redesign of Perl 5 in 2000, eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from each other. The Perl languages borrow features from other programming languages including C, sh, AWK, and sed; They provide text processing facilities without the arbitrary da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apache FreeMarker
Apache FreeMarker is a free Java-based template engine, originally focusing on dynamic web page generation with MVC software architecture. However, it is a general purpose template engine, with no dependency on servlets or HTTP or HTML, and is thus often used for generating source code, configuration files or e-mails. History FreeMarker had a somewhat hectic history until about 2004, caused by paradigm shifts and other significant changes on multiple occasions. FreeMarker 1 (now known as FreeMarker Classic, a separate project) was originally written by Benjamin Geer and Mike Bayer. From 2002, the new project lead was Jonathan Revusky, who released FreeMarker 2, which started a sequence of several substantial changes. The main goal of the changes was to make the template language more strict, i.e., to detect as many of the typos and other typical mistakes as possible. Also, automatic object wrapping was introduced, along with gradual advancement of the type system of the tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tagged Union
In computer science, a tagged union, also called a variant, variant record, choice type, discriminated union, disjoint union, sum type or coproduct, is a data structure used to hold a value that could take on several different, but fixed, types. Only one of the types can be in use at any one time, and a tag field explicitly indicates which one is in use. It can be thought of as a type that has several "cases", each of which should be handled correctly when that type is manipulated. This is critical in defining recursive datatypes, in which some component of a value may have the same type as the value itself, for example in defining a type for representing trees, where it is necessary to distinguish multi-node subtrees and leaves. Like ordinary unions, tagged unions can save storage by overlapping storage areas for each type, since only one is in use at a time. Description Tagged unions are most important in functional languages such as ML and Haskell, where they are called datat ... [...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 gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ternary Operators
In mathematics, a ternary operation is an ''n''- ary operation with ''n'' = 3. A ternary operation on a set ''A'' takes any given three elements of ''A'' and combines them to form a single element of ''A''. In computer science, a ternary operator is an operator that takes three arguments as input and returns one output. Examples The function T(a, b, c) = ab + c is an example of a ternary operation on the integers (or on any structure where + and \times are both defined). Properties of this ternary operation have been used to define planar ternary rings in the foundations of projective geometry. In the Euclidean plane with points ''a'', ''b'', ''c'' referred to an origin, the ternary operation , b, c= a - b + c has been used to define free vectors. Since (''abc'') = ''d'' implies ''a'' – ''b'' = ''c'' – ''d'', these directed segments are equipollent and are associated with the same free vector. Any three points in the plane ''a, b, c'' thus determine a parallelogram w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objective-C (programming Language)
Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXTSTEP operating system. Due to Apple macOS’s direct lineage from NeXTSTEP, Objective-C was the standard programming language used, supported, and promoted by Apple for developing macOS and iOS applications (via their respective APIs, Cocoa and Cocoa Touch) until the introduction of the Swift programming language in 2014. Objective-C programs developed for non-Apple operating systems or that are not dependent on Apple's APIs may also be compiled for any platform supported by GNU GCC or LLVM/Clang. Objective-C source code 'messaging/implementation' program files usually have filename extensions, while Objective-C 'header/interface' files have extensions, the same as C header files. Objective-C++ files are denoted with a file extension. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groovy (programming Language)
Apache Groovy is a Java-syntax-compatible object-oriented programming language for the Java platform. It is both a static and dynamic language with features similar to those of Python, Ruby, and Smalltalk. It can be used as both a programming language and a scripting language for the Java Platform, is compiled to Java virtual machine (JVM) bytecode, and interoperates seamlessly with other Java code and libraries. Groovy uses a curly-bracket syntax similar to Java's. Groovy supports closures, multiline strings, and expressions embedded in strings. Much of Groovy's power lies in its AST transformations, triggered through annotations. Groovy 1.0 was released on January 2, 2007, and Groovy 2.0 in July, 2012. Since version 2, Groovy can be compiled statically, offering type inference and performance near that of Java. Groovy 2.4 was the last major release under Pivotal Software's sponsorship which ended in March 2015. Groovy has since changed its governance structure to a Proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kotlin (programming Language)
Kotlin () is a cross-platform, statically typed, general-purpose programming language with type inference. Kotlin is designed to interoperate fully with Java, and the JVM version of Kotlin's standard library depends on the Java Class Library, but type inference allows its syntax to be more concise. Kotlin mainly targets the JVM, but also compiles to JavaScript (e.g., for frontend web applications using React) or native code via LLVM (e.g., for native iOS apps sharing business logic with 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 app developers. Since the release of Android Studio 3.0 in October 2017, Kotlin has been included as an alternative to the standard Java compiler. The Android Kotlin compiler produces Java 8 bytecode by default (which runs in any later JVM), but lets the pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JavaScript Syntax
The syntax of JavaScript is the set of rules that define a correctly structured JavaScript program. The examples below make use of the log function of the console object present in most browsers for standard text output. The JavaScript standard library lacks an official standard text output function (with the exception of document.write). Given that JavaScript is mainly used for client-side scripting within modern web browsers, and that almost all Web browsers provide the alert function, alert can also be used, but is not commonly used. Origins Brendan Eich summarized the ancestry of the syntax in the first paragraph of the JavaScript 1.1 specification as follows: Basics Case sensitivity JavaScript is case sensitive. It is common to start the name of a constructor with a capitalised letter, and the name of a function or variable with a lower-case letter. Example: var a = 5; console.log(a); // 5 console.log(A); // throws a ReferenceError: A is not defined Whitespace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TypeScript
TypeScript is a free and open source programming language 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 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). Multiple options are available for transpilation. The default TypeScript Compiler can be used, or the Babel compiler can be invoked to convert TypeScript to JavaScript. TypeScript supports definition files that can contain type information of existing JavaScript libraries, much like C++ header files can describe the structure of existing object files. This enables other programs to use the values defined in the files as if they were statically typed TypeScript entitie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Babel (compiler)
Babel is a free and open-source JavaScript transcompiler that is mainly used to convert ECMAScript 2015+ (ES6+) code into backwards-compatible JavaScript code that can be run by older JavaScript engines. It allows web developers to take advantage of the newest features of the language. Developers can use new JavaScript language features by using Babel to convert their source code into versions of JavaScript that a Web browser can process. Babel is used to compile TypeScript into JavaScript. The core version of Babel was downloaded 5 million times a month in 2016, and this increased to 16 million times a week in 2019. Babel plugins transform syntax that is not widely supported into a backward-compatible version. For example, arrow functions, which are specified in ES6, are converted into regular function declarations. Non-standard JavaScript syntax such as JSX can also be transformed. Babel can automatically inject polyfills provided by core-js for support features that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecma International
Ecma International () is a nonprofit standards organization for information and communication systems. It acquired its current name in 1994, when the European Computer Manufacturers Association (ECMA) changed its name to reflect the organization's global reach and activities. As a consequence, the name is no longer considered an acronym and no longer uses full capitalization. The organization was founded in 1961 to standardize computer systems in Europe. Membership is open to large and small companies worldwide that produce, market, or develop computer or communication systems, and have interest and experience in the areas addressed by the group's technical bodies. It is located in Geneva. Aims Ecma aims to develop standards and technical reports to facilitate and standardize the use of information communication technology and consumer electronics; encourage the correct use of standards by influencing the environment in which they are applied; and publish these standards and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
