Introduction to Programming Languages

Overview

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely.

The earliest programming languages predate the invention of the computer, and were used to direct the behavior of machines such as Jacquard looms and player pianos. Thousands of different programming languages have been created, mainly in the computer field, with many more being created every year. Most programming languages describe computation in an imperative style, i.e., as a sequence of commands, although some languages, such as those that support functional programming or logic programming, use alternative forms of description.

Definitions

A programming language is a notation for writing programs, which are specifications of a computation or algorithm. Some, but not all, authors restrict the term “programming language” to those languages that can express all possible algorithms. Traits often considered important for what constitutes a programming language include:

Function and target: A computer programming language is a language used to write computer programs, which involve a computer performing some kind of computation or algorithm and possibly control external devices such as printers, disk drives, robots, and so on. For example PostScript programs are frequently created by another program to control a computer printer or display. More generally, a programming language may describe computation on some, possibly abstract, machine. It is generally accepted that a complete specification for a programming language includes a description, possibly idealized, of a machine or processor for that language. In most practical contexts, a programming language involves a computer; consequently, programming languages are usually defined and studied this way. Programming languages differ from natural languages in that natural languages are only used for interaction between people, while programming languages also allow humans to communicate instructions to machines.

Markup languages like XML, HTML or troff, which define structured data, are not generally considered programming languages. Programming languages may, however, share the syntax with markup languages if a computational semantics is defined. XSLT, for example, is a Turing complete XML dialect. Moreover, LaTeX, which is mostly used for structuring documents, also contains a Turing complete subset.

The term computer language is sometimes used interchangeably with programming language. However, the usage of both terms varies among authors, including the exact scope of each. One usage describes programming languages as a subset of computer languages. In this vein, languages used in computing that have a different goal than expressing computer programs are generically designated computer languages. For instance, markup languages are sometimes referred to as computer languages to emphasize that they are not meant to be used for programming. Another usage regards programming languages as theoretical constructs for programming abstract machines, and computer languages as the subset thereof that runs on physical computers, which have finite hardware resources. John C. Reynolds emphasizes that formal specification languages are just as much programming languages as are the languages intended for execution. He also argues that textual and even graphical input formats that affect the behavior of a computer are programming languages, despite the fact they are commonly not Turing-complete, and remarks that ignorance of programming language concepts is the reason for many flaws in input formats.

Learning Objectives

* What is a programming language and how are the used
* What are the most popular usages for programming languages
* Learn the Programming Language Popularity index and cite the top ten most popular program languages

Activities

Watch the following video and review the linked resources to respond to the Learning Objectives listed above

Programming Language Popularity index

From the author

Last data update: Wed Apr 13 14:57:11 +0200 2011

We have attempted to collect a variety of data about the relative popularity of programming languages, mostly out of curiousity. To some degree popularity does matter – however it is clearly not the only thing to take into account when choosing a programming language. Most experienced programmers should be able to learn the basics of a new language in a week, and be productive with it in a few more weeks, although it will likely take much longer to truly master it.

Browser requirements: sadly, yes, this site requires a browser that supports Javascript and the canvas tag. I wasn’t happy with other options for creating charts in image formats, and this also saves some bandwidth, since the Javascript is only downloaded once. Firefox, IE and Safari ought to work, although I haven’t tested it with the latter. Konqueror apparently does not work. The charts are created with Chartr and Flotr.

Note: these results are not scientific. They are interesting nonetheless, and are an attempt to glean as much data as possible notwithstanding the fact that gathering precise data is impossible. We hope you find them interesting as well. Constructive suggestions on improving them are welcome. Contact information is provided at the bottom of the page.

image programingpopularityindex

Langpop.com

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