Editing Programming paradigm (section)

== Languages and paradigms ==

=== Machine code ===

[[Machine code]] is the lowest-level of computer programming as it is [[Instruction set|machine instructions]] that define behavior at the lowest level of abstract possible for a computer. As it is the most prescriptive way to code it is classified as imperative.

It is sometimes called the [[first-generation programming language]].

=== Assembly ===

[[Assembly language]] introduced mnemonics for machine instructions and [[memory address]]es. Assembly is classified as imperative and is sometimes called the [[second-generation programming language]].

In the 1960s, assembly languages were developed to support library COPY and quite sophisticated conditional macro generation and preprocessing abilities, CALL to [[subroutine]], external variables and common sections (globals), enabling significant code re-use and isolation from hardware specifics via the use of logical operators such as READ/WRITE/GET/PUT. Assembly was, and still is, used for time-critical systems and often in [[embedded system]]s as it gives the most control of what the machine does.

=== Procedural languages ===

[[Procedural language]]s, also called the [[third-generation programming language]]s are the first described as [[high-level programming language|high-level languages]]. They support vocabulary related to the problem being solved. For example,
* COmmon Business Oriented Language ([[COBOL]]){{snd}} uses terms like [[computer file|file]], [[move (command)|move]] and [[copy (command)|copy]].
* FORmula TRANslation ([[FORTRAN]]){{snd}} using [[mathematical]] language terminology, it was developed mainly for scientific and engineering problems.
* ALGOrithmic Language ([[ALGOL]]){{snd}} focused on being an appropriate language to define [[algorithm]]s, while using mathematical language terminology, targeting scientific and engineering problems, just like FORTRAN.
* Programming Language One ([[PL/I]]){{snd}} a hybrid commercial-scientific general purpose language supporting [[pointer (computer programming)|pointer]]s.
* Beginners All purpose Symbolic Instruction Code ([[BASIC]]){{snd}} it was developed to enable more people to write programs.
* [[C (programming language)|C]]{{snd}} a general-purpose programming language, initially developed by [[Dennis Ritchie]] between 1969 and 1973 at [[AT&T Bell Labs]].

These languages are classified as procedural paradigm. They directly control the step by step process that a computer program follows. The [[efficacy]] and [[algorithmic efficiency|efficiency]] of such a program is therefore highly dependent on the programmer's skill.

=== Object-oriented programming ===

{{Main|Object-oriented programming}}

In attempt to improve on procedural languages, [[object-oriented programming]] (OOP) languages were created, such as [[Simula]], [[Smalltalk]], [[C++]], [[Eiffel (programming language)|Eiffel]], [[Python (programming language)|Python]], [[PHP]], [[Java (programming language)|Java]], and [[C Sharp (programming language)|C#]]. In these languages, [[data]] and methods to manipulate the data are in the same code unit called an [[object (computer science)|object]]. This [[Encapsulation (computer programming)|encapsulation]] ensures that the only way that an object can access data is via ''[[Method (computer programming)|methods]]'' of the object that contains the data. Thus, an object's inner workings may be changed without affecting code that uses the object. 

There is [[Object-oriented programming#Criticism|controversy]] raised by [[Alexander Stepanov]], [[Richard Stallman]]<ref>{{cite web|url=http://groups.google.com/group/comp.emacs.xemacs/browse_thread/thread/d0af257a2837640c/37f251537fafbb03?lnk=st&q=%22Richard+Stallman%22+oop&rnum=5&hl=en#37f251537fafbb03|title=Mode inheritance, cloning, hooks & OOP (Google Groups Discussion)}}</ref> and other programmers, concerning the efficacy of the OOP paradigm versus the procedural paradigm. The need for every object to have associative methods leads some skeptics to associate OOP with [[software bloat]]; an attempt to resolve this dilemma came through [[Polymorphism (computer science)|polymorphism]].

Although most OOP languages are third-generation, it is possible to create an object-oriented assembler language. [[High Level Assembly]] (HLA) is an example of this that fully supports advanced data types and object-oriented assembly language programming{{snd}} despite its early origins. Thus, differing programming paradigms can be seen rather like ''motivational [[meme]]s'' of their advocates, rather than necessarily representing progress from one level to the next.{{Citation needed|date=March 2018}} Precise comparisons of competing paradigms' efficacy are frequently made more difficult because of new and differing terminology applied to similar entities and processes together with numerous implementation distinctions across languages.

=== Declarative languages ===

A [[declarative programming]] program describes what the problem is, not how to solve it. The program is structured as a set of properties to find in the expected result, not as a procedure to follow. Given a database or a set of rules, the computer tries to find a solution matching all the desired properties. An archetype of a declarative language is the [[fourth-generation programming language|fourth generation language]] [[SQL]], and the family of functional languages and logic programming.

[[Functional programming]] is a subset of declarative programming. Programs written using this paradigm use [[subroutine|functions]], blocks of code intended to behave like [[function (mathematics)|mathematical functions]]. Functional languages discourage changes in the value of variables through [[assignment (computer science)|assignment]], making a great deal of use of [[recursion (computer science)|recursion]] instead.

The [[logic programming]] paradigm views computation as [[automated reasoning]] over a body of knowledge. Facts about the [[domain (software engineering)|problem domain]] are expressed as logic formulas, and programs are executed by applying [[inference rule]]s over them until an answer to the problem is found, or the set of formulas is proved inconsistent.

=== Other paradigms ===

[[Symbolic programming]] is a paradigm that describes programs able to manipulate formulas and program components as data.<ref name="symbolic-programming-lisp"/> Programs can thus effectively modify themselves, and appear to "learn", making them suited for applications such as [[artificial intelligence]], [[expert system]]s, [[natural-language processing]] and computer games. Languages that support this paradigm include [[Lisp (programming language)|Lisp]] and [[Prolog]].<ref>{{cite web
 |url=http://www.allbusiness.com/glossaries/symbolic-programming/4950308-1.html
 |title=Business glossary: Symbolic programming definition
 |access-date=2014-07-30
 |website=allbusiness.com
}}</ref>

[[Differentiable programming]] structures programs so that they can be [[Differentiation (mathematics)|differentiated]] throughout, usually via [[automatic differentiation]].<ref>{{Citation|last1=Wang|first1=Fei|title=Backpropagation with Callbacks: Foundations for Efficient and Expressive Differentiable Programming|date=2018|url=http://papers.nips.cc/paper/8221-backpropagation-with-callbacks-foundations-for-efficient-and-expressive-differentiable-programming.pdf|work=Advances in Neural Information Processing Systems 31|pages=10201–10212|editor-last=Bengio|editor-first=S.|publisher=Curran Associates, Inc.|access-date=2019-02-13|last2=Decker|first2=James|last3=Wu|first3=Xilun|last4=Essertel|first4=Gregory|last5=Rompf|first5=Tiark|editor2-last=Wallach|editor2-first=H.|editor3-last=Larochelle|editor3-first=H.|editor4-last=Grauman|editor4-first=K.}}</ref><ref name="innes">{{Cite journal|last1=Innes|first1=Mike|date=2018|title=On Machine Learning and Programming Languages|url=http://www.sysml.cc/doc/37.pdf|journal=SysML Conference 2018|access-date=2019-02-13|archive-url=https://web.archive.org/web/20180920175619/http://www.sysml.cc/doc/37.pdf|archive-date=2018-09-20|url-status=dead}}</ref>

[[Literate programming]], as a form of [[imperative programming]], structures programs as a human-centered web, as in a [[hypertext]] essay: documentation is integral to the program, and the program is structured following the logic of prose exposition, rather than compiler convenience.

[[Symbolic programming]] techniques such as [[reflective programming]] (reflection), which allow a program to refer to itself, might also be considered as a programming paradigm. However, this is compatible with the major paradigms and thus is not a real paradigm in its own right.