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Programming language

1,292 bytes added, 23:24, February 29, 2012
clarify, avoid or explain some technical terms, expand
A '''programming language''' is an artificial [[language]] used mainly for giving instructions to computers; a secondary use is for the precise specification of [[algorithm]]s. A group of instructions for a particular purpose is known as a [[computer program]].
Compared When compared with human languages (e.g. English, French, Spanish, etc.), programming languages are very much smaller, much simpler, and are also more precise. Most programming languages are consist of a mixture of English words and mathematical notation; very few programming languages have a base vocabulary exceeding 60 words, although they may also have utility libraries with hundreds of entries which provide optional extra functionality. The [[Context-Free Grammar|context-free grammars]] commonly used to precisely define the [[syntax]] of programming languages are not powerful enough to define human languages such as English.
Many thousands of different programming languages have been defined, though only a few dozen are in widespread use. The first publicly available programming language was A-0, developed in 1951 by Grace Hopper. In 1948 Zuse published a paper (in "Archiv der Mathematik") about an early programming language Plankalkül, though this was not actually implemented until 1998 .  ==Describing a programming language==While human languages such as English may have rules of grammar, there are almost always exceptions to these rules. To reduce ambiguity, most programming languages have their [[grammar]] or syntax rigidly defined by a relatively small number of rules, with no exceptions. In many cases some variation of a [[Context-Free Grammar|context-free grammar]] is used, often Backus-Naur Form, or some extension thereof. Note that context-free grammars are not powerful enough to describe human languages such as English. The meaning or [[semantics]] of any particular construct in a programming language is most commonly described in fairly precise English. Several unsuccessful attempts have been made to find a formal way of describing the semantics. The more important programming languages have an internationally-agreed official standard (publication was ISO is the international standards organisation, ANSI is the standards body in "Archiv der Mathematik"the United States). In theory, programs which conform to the relevant standard should be usable on most types of computer; this works in practice most of the time, provided that the programmers have been careful to avoid machine-dependencies. Very few programmers learn a programming language directly from the formal definition, which exists primarily as a reference which can be consulted in cases of doubt. There are usually plenty of books and or training courses for the more common programming languages.
==About programming languages==
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