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Compile-time Function Execution
In computing, compile-time function execution (or compile time function evaluation, or general constant expressions) is the ability of a compiler, that would normally compile a function to machine code and execute it at run time, to execute the function at compile time. This is possible if the arguments to the function are known at compile time, and the function does not make any reference to or attempt to modify any global state (i.e. it is a pure function). If the value of only some of the arguments are known, the compiler may still be able to perform some level of compile-time function execution ( partial evaluation), possibly producing more optimized code than if no arguments were known. Examples Lisp The Lisp macro system is an early example of the use of compile-time evaluation of user-defined functions in the same language. C++ The Metacode extension to C++ (Vandevoorde 2003) was an early experimental system to allow compile-time function evaluation (CTFE) and code inject ... [...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] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, engineering, mathematical, technological and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology and software engineering. The term "computing" is also synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. Computing is intimately tied to the representation of numbers, though mathematical conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Template Metaprogramming
Template metaprogramming (TMP) is a metaprogramming technique in which templates are used by a compiler to generate temporary source code, which is merged by the compiler with the rest of the source code and then compiled. The output of these templates can include compile-time constants, data structures, and complete functions. The use of templates can be thought of as compile-time polymorphism. The technique is used by a number of languages, the best-known being C++, but also Curl, D, Nim, and XL. Template metaprogramming was, in a sense, discovered accidentally. Some other languages support similar, if not more powerful, compile-time facilities (such as Lisp macros), but those are outside the scope of this article. Components of template metaprogramming The use of templates as a metaprogramming technique requires two distinct operations: a template must be defined, and a defined template must be instantiated. The template definition describes the generic form of the gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler Construction
In computing, a compiler is a computer program that Translator (computing), translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a lower level language, low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program.Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A ''cross-compiler'' produces code for a different Central processing unit, CPU or operating system than the one on which the cross-compiler itself runs. A ''bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D Programming Language
D, also known as dlang, is a multi-paradigm system programming language created by Walter Bright at Digital Mars and released in 2001. Andrei Alexandrescu joined the design and development effort in 2007. Though it originated as a re-engineering of C++, D is a profoundly different language —features of D can be considered streamlined and expanded-upon ideas from C++, however D also draws inspiration from other high-level programming languages, notably Java, Python, Ruby, C#, and Eiffel. D combines the performance and safety of compiled languages with the expressive power of modern dynamic and functional programming languages. Idiomatic D code is commonly as fast as equivalent C++ code, while also being shorter. The language as a whole is not memory-safe but includes optional attributes designed to guarantee memory safety of either subsets of or the whole program. Type inference, automatic memory management and syntactic sugar for common types allow faster development, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C++20
C++20 is a version of the ISO/IEC 14882 standard for the C++ programming language. C++20 replaced the prior version of the C++ standard, called C++17. The standard was technically finalized by WG21 at the meeting in Prague in February 2020, approved on 4 September 2020, and published in December 2020. Features C++20 adds more new major features than C++14 or C++17. Changes that have been accepted into C++20 include: Language * concepts, with terse syntax * modules * designated initializers (based on the C99 feature, and common g++ extension) * , this/code> as a lambda capture * template parameter lists on lambdas * three-way comparison using the "spaceship operator", operator <=> * initialization of an additional variable within a range-based for statement * lambdas in unevaluated contexts * default constructible and assignable stateless lambdas * allow pack expansions in lambda ''init-capture'' * class types in non-type template parameters, also allowing string ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C++14
C++14 is a version of the ISO/IEC 14882 standard for the C++ programming language. It is intended to be a small extension over C++11, featuring mainly bug fixes and small improvements, and was replaced by C++17. Its approval was announced on August 18, 2014. C++14 was published as ISO/IEC 14882:2014 in December 2014. Because earlier C++ standard revisions were noticeably late, the name "C++1y" was sometimes used instead until its approval, similarly to how the C++11 standard used to be termed "C++0x" with the expectation of its release before 2010 (although in fact it slipped into 2010 and finally 2011). New language features These are the features added to the core language of C++14. Function return type deduction C++11 allowed lambda functions to deduce the return type based on the type of the expression given to the return statement. C++14 provides this ability to all functions. It also extends these facilities to lambda functions, allowing return type deduction for func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C++11
C++11 is a version of the ISO/IEC 14882 standard for the C++ programming language. C++11 replaced the prior version of the C++ standard, called C++03, and was later replaced by C++14. The name follows the tradition of naming language versions by the publication year of the specification, though it was formerly named ''C++0x'' because it was expected to be published before 2010. Although one of the design goals was to prefer changes to the libraries over changes to the core language, C++11 does make several additions to the core language. Areas of the core language that were significantly improved include multithreading support, generic programming support, uniform initialization, and performance. Significant changes were also made to the C++ Standard Library, incorporating most of the C++ Technical Report 1 (TR1) libraries, except the library of mathematical special functions. C++11 was published as ''ISO/IEC 14882:2011'' in September 2011 and is available for a fee. The worki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Evaluation
In computing, partial evaluation is a technique for several different types of program optimization by specialization. The most straightforward application is to produce new programs that run faster than the originals while being guaranteed to behave in the same way. A computer program ''prog'' is seen as a mapping of input data into output data: : prog : I_\text \times I_\text \to O, where I_\text, the ''static data'', is the part of the input data known at compile time. The partial evaluator transforms \langle prog, I_\text\rangle into prog^* : I_\text \to O by precomputing all static input at compile time. prog^* is called the "residual program" and should run more efficiently than the original program. The act of partial evaluation is said to "residualize" prog to prog^*. Futamura projections A particularly interesting example of the use of partial evaluation, first described in the 1970s by Yoshihiko Futamura, is when ''prog'' is an interpreter for a programming languag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macro (computer Science)
In computer programming, a macro (short for "macro instruction"; ) is a rule or pattern that specifies how a certain input should be mapped to a replacement output. Applying a macro to an input is known as macro expansion. The input and output may be a sequence of lexical tokens or characters, or a syntax tree. Character macros are supported in software applications to make it easy to invoke common command sequences. Token and tree macros are supported in some programming languages to enable code reuse or to extend the language, sometimes for domain-specific languages. Macros are used to make a sequence of computing instructions available to the programmer as a single program statement, making the programming task less tedious and less error-prone. (Thus, they are called "macros" because a "big" block of code can be expanded from a "small" sequence of characters.) Macros often allow positional or keyword parameters that dictate what the conditional assembler program generates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program. Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A ''cross-compiler'' produces code for a different CPU or operating system than the one on which the cross-compiler itself runs. A ''bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software include, a program that translates from a low-level language to a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pure Function
In computer programming, a pure function is a function that has the following properties: # the function return values are identical for identical arguments (no variation with local static variables, non-local variables, mutable reference arguments or input streams), and # the function has no side effects (no mutation of local static variables, non-local variables, mutable reference arguments or input/output streams). Thus a pure function is a computational analogue of a mathematical function. Some authors, particularly from the imperative language community, use the term "pure" for all functions that just have the above property 2 (discussed below). Examples Pure functions The following examples of C++ functions are pure: Impure functions The following C++ functions are impure as they lack the above property 1: The following C++ functions are impure as they lack the above property 2: The following C++ functions are impure as they lack both the above properties 1 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
