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Immutable Value
In object-oriented and functional programming, an immutable object (unchangeable object) is an object whose state cannot be modified after it is created.Goetz et al. ''Java Concurrency in Practice''. Addison Wesley Professional, 2006, Section 3.4. Immutability This is in contrast to a mutable object (changeable object), which can be modified after it is created. In some cases, an object is considered immutable even if some internally used attributes change, but the object's state appears unchanging from an external point of view. For example, an object that uses memoization to cache the results of expensive computations could still be considered an immutable object. Strings and other concrete objects are typically expressed as immutable objects to improve readability and runtime efficiency in object-oriented programming. Immutable objects are also useful because they are inherently thread-safe. Other benefits are that they are simpler to understand and reason about and offer h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Computer 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 im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruby Programming Language
Ruby is an interpreted, high-level, general-purpose programming language which supports multiple programming paradigms. It was designed with an emphasis on programming productivity and simplicity. In Ruby, everything is an object, including primitive data types. It was developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan. Ruby is dynamically typed and uses garbage collection and just-in-time compilation. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, BASIC, Java and Lisp. History Early concept Matsumoto has said that Ruby was conceived in 1993. In a 1999 post to the ''ruby-talk'' mailing list, he describes some of his early ideas about the language: Matsumoto describes the design of Ruby as being like a simple Lisp language at its core, with an object system like that of Smalltalk, blocks inspired by higher-or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NET Framework
The .NET Framework (pronounced as "''dot net"'') is a proprietary software framework developed by Microsoft that runs primarily on Microsoft Windows. It was the predominant implementation of the Common Language Infrastructure (CLI) until being superseded by the cross-platform .NET project. It includes a large class library called Framework Class Library (FCL) and provides language interoperability (each language can use code written in other languages) across several programming languages. Programs written for .NET Framework execute in a software environment (in contrast to a hardware environment) named the Common Language Runtime (CLR). The CLR is an application virtual machine that provides services such as security, memory management, and exception handling. As such, computer code written using .NET Framework is called "managed code". FCL and CLR together constitute the .NET Framework. FCL provides the user interface, data access, database connectivity, cryptograp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced like the letter c'') is a General-purpose language, general-purpose computer 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 CPUs. It has found lasting use in operating systems, device drivers, protocol stacks, though decreasingly for application software. 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 measuring programming language popularity, most widely used programming languages, with C compilers avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Const Correctness
In some programming languages, const is a type qualifier (a keyword applied to a data type) that indicates that the data is read-only. While this can be used to declare constants, in the C family of languages differs from similar constructs in other languages in being part of the ''type,'' and thus has complicated behavior when combined with pointers, references, composite data types, and type-checking. In other languages, the data is not in a single memory location, but copied at compile time on each use. Languages which utilize it include C, C++, D, JavaScript, Julia, and Rust. Introduction When applied in an object declaration, it indicates that the object is a constant: its value may not be changed, unlike a variable. This basic use – to declare constants – has parallels in many other languages. However, unlike in other languages, in the C family of languages the const is part of the ''type'', not part of the ''object''. For example, in C, declares an objec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compile-time
In computer science, compile time (or compile-time) describes the time window during which a computer program is compiled. The term is used as an adjective to describe concepts related to the context of program compilation, as opposed to concepts related to the context of program execution ( runtime). For example, ''compile-time requirements'' are programming language requirements that must be met by source code before compilation and ''compile-time properties'' are properties of the program that can be reasoned about during compilation. The actual length of time it takes to compile a program is usually referred to as ''compilation time''. Compile time/Early binding vs Run time The determination of execution model have been set during the compile time stage. Run time- the method of execution and allocation - have been set during the run time and are based on the run time dynamicity. Overview Most compilers have at least the following compiler phases (which therefore occur at c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Storage
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but less expensive and larger options further away. Generally, the fast volatile technologies (which lose data when off power) are referred to as "memory", while slower persistent technologies are referred to as "storage". Even the first computer designs, Charles Babbage's Analytical Engine and Percy Ludgate's Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction was extended in the Von Neumann a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread-safe
Thread safety is a computer programming concept applicable to multi-threaded code. Thread-safe code only manipulates shared data structures in a manner that ensures that all threads behave properly and fulfill their design specifications without unintended interaction. There are various strategies for making thread-safe data structures. A program may execute code in several threads simultaneously in a shared address space where each of those threads has access to virtually all of the memory of every other thread. Thread safety is a property that allows code to run in multithreaded environments by re-establishing some of the correspondences between the actual flow of control and the text of the program, by means of synchronization. Levels of thread safety Software libraries can provide certain thread-safety guarantees. For example, concurrent reads might be guaranteed to be thread-safe, but concurrent writes might not be. Whether a program using such a library is thread-safe depen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fast Path
Fast path is a term used in computer science to describe a path with shorter instruction path length through a program compared to the normal path. For a fast path to be effective it must handle the most commonly occurring tasks more efficiently than the normal path, leaving the latter to handle uncommon cases, corner cases, error handling, and other anomalies. Fast paths are a form of optimization. For example dedicated packet routing hardware used to build computer networks will often support software dedicated to handling the most common kinds of packets, with other kinds, for example with control information or packets directed at the device itself instead of being routed elsewhere, put on the metaphorical "slow path", in this example usually implemented by software running on the control processor. Specific implementations of networking software architectures have been developed that leverage the concept of a fast path to maximize the performance of packet processing software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String Intern Pool
In computer science, string interning is a method of storing only one copy of each distinct string value, which must be immutable. Interning strings makes some string processing tasks more time- or space-efficient at the cost of requiring more time when the string is created or interned. The distinct values are stored in a string intern pool. The single copy of each string is called its ''intern'' and is typically looked up by a method of the string class, for example String.intern() in Java. All compile-time constant strings in Java are automatically interned using this method. String interning is supported by some modern object-oriented programming languages, including Java, Python, PHP (since 5.4), Lua and .NET languages. Lisp, Scheme, Julia, Ruby and Smalltalk are among the languages with a symbol type that are basically interned strings. The library of the Standard ML of New Jersey contains an atom type that does the same thing. Objective-C's selectors, which are mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intern (computer Science)
In computer science, string interning is a method of storing only one copy of each distinct string value, which must be immutable. Interning strings makes some string processing tasks more time- or space-efficient at the cost of requiring more time when the string is created or interned. The distinct values are stored in a string intern pool. The single copy of each string is called its ''intern'' and is typically looked up by a method of the string class, for example String.intern() in Java. All compile-time constant strings in Java are automatically interned using this method. String interning is supported by some modern object-oriented programming languages, including Java, Python, PHP (since 5.4), Lua and .NET languages. Lisp, Scheme, Julia, Ruby and Smalltalk are among the languages with a symbol type that are basically interned strings. The library of the Standard ML of New Jersey contains an atom type that does the same thing. Objective-C's selectors, which are mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Memory
In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very large (main) memory". The computer's operating system, using a combination of hardware and software, maps memory addresses used by a program, called '' virtual addresses'', into ''physical addresses'' in computer memory. Main storage, as seen by a process or task, appears as a contiguous address space or collection of contiguous segments. The operating system manages virtual address spaces and the assignment of real memory to virtual memory. Address translation hardware in the CPU, often referred to as a memory management unit (MMU), automatically translates virtual addresses to physical addresses. Software within the operating system may extend these capabilities, utilizing, e.g., disk storage, to provide a virtual address space tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
