NationMaster - Encyclopedia: Markup language

A markup language combines text and extra information about the text. The extra information, for example about the text's structure or presentation, is expressed using markup, which is intermingled with the primary text. The best-known markup language in modern use is HTML (HyperText Markup Language), one of the foundations of the World Wide Web. Originally markup was used in the publishing industry in the communication of printed work between authors, editors, and printers. LEXX Editor for the OED, sample entry (segment of) This is a front-of-screen photograph from a 3279 mainframe-attached screen, taken with an Olympus (I think) 35mm camera in late 1985 or early 1986. ... The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ... The Oxford English Dictionary print set The Oxford English Dictionary (OED) is a dictionary published by the Oxford University Press (OUP), and is generally regarded as the most comprehensive and scholarly dictionary of the English language. ... HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ... HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ... In computing, hypertext is a user interface paradigm for displaying documents which, according to an early definition (Nelson 1970), branch or perform on request. ... Graphic representation of the world wide web around Wikipedia The World Wide Web (WWW, or simply Web) is an information space in which the items of interest, referred to as resources, are identified by global identifiers called Uniform Resource Identifiers (URI). ...

Classes of markup languages

Markup languages are often divided into three classes: presentational, procedural, and descriptive.

Presentational markup

Presentational markup is an attempt to infer document structure from cues in the encoding. For example, in a text file, the title of a document might be preceded by several newlines and/or spaces, thus suggesting leading spacing and centering. Word-processing and desktop publishing products sometimes attempt to deduce structure from such conventions, but, as the enormous variety of Wiki plain-text conventions prove, this is, as of yet, an unresolved problem. It has been suggested that this article or section be merged with Plain text. ... Adobe InDesign CS2, one of many popular desktop publishing applications. ...

Procedural markup

Procedural markup is typically also focused on the presentation of text, but is usually visible to the user editing the text file, and is expected to be interpreted by software in the order in which it appears. To format a title, a succession of formatting directives would be inserted into the file immediately before the title's text, instructing software to switch into centered display mode, then enlarge and embolden the typeface. The title text would be followed by directives to reverse these effects; in more advanced systems macros or a stack model make this less tedious. In most cases, the procedural markup capabilities comprise a Turing-complete programming language. Examples of procedural-markup systems include nroff, troff, TeX and Lout. Procedural markup has been widely used in professional publishing applications, where professional typographers can be expected to learn the languages required. Look up Stack in Wiktionary, the free dictionary. ... In computability theory a programming language or any other logical system is called Turing-complete if it has a computational power equivalent to a universal Turing machine. ... The title given to this article is incorrect due to technical limitations. ... Troff is a document processing system developed by AT&T for the Unix operating system. ... TeX (IPA: as in Greek, often in English; written with a lowercase e in imitation of the logo) is a typesetting system created by Donald Knuth. ... Lout is a batch document formatter. ... Pande ...

Descriptive markup

Descriptive markup or semantic markup applies labels to fragments of text without necessarily mandating any particular display or other processing semantics. For example, the Atom syndication language provides markup to label the "updated" time-stamp, which is an assertion from the publisher as to when some item of information was last changed. While the Atom specification discusses the meaning of the "updated" timestamp, and specifies the markup used to identify it, it makes no assertions about whether or how it might be presented to a user. Software might put this markup to a variety of uses, including many not foreseen by the designers of the Atom language. SGML and XML are systems explicitly designed to support the design of descriptive markup languages. The name Atom applies to a pair of related standards. ... The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ... The Extensible Markup Language (XML) is a general-purpose markup language. ...

In practice, the classes of markup usually co-occur in any given system. For example, HTML contains markup elements which are purely procedural (for example b for bold) and others which are purely descriptive ("blockquote", or the "href=" attribute). HTML also includes the PRE element, which encloses areas of presentational markup to be laid out exactly as typed. HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ...

Sets of markup elements and rules for their use are commonly developed by standards bodies to support the kinds of documents used in particular industries or communities. One of the earliest of these was CALS, used by the US military for technical manuals. Industries with large-scale documentation requirements soon followed suit, developing tag-sets for aircraft, telecommunications, automotive, and computer hardware manuals. This led to delivering many such manuals solely in electronic form; some companies were able to produce printed, online, and CD-based manuals all from a single (descriptive markup) source. A notable example was Sun Microsystems, where Jon Bosak (who later founded the XML committee) decided on SGML for multi-target documentation delivery, achieving considerable cost savings. Computer-Aided Acquisition and Logistic Support (CALS) is a strategy for paperless process control. ... Sun Microsystems, Inc. ... Jon Bosak led the creation of the XML specification at the W3C. Tim Bray, who was one of the editors of the XML specification, has this to say in his note on Bosak in his annotated version of the spec: Jon Bosak is the single person without whose efforts XML... The Extensible Markup Language (XML) is a general-purpose markup language. ...

Markup languages now abound; among the more widely known are DocBook, MathML, SVG, Open eBook, TEI, and XBRL. Many are for various kinds of text documents, but specialized languages are used in many other domains. DocBook is a markup language for technical documentation, originally intended for authoring technical documents related to computer hardware and software but which can be used for any other sort of documentation. ... Mathematical Markup Language (MathML) is an application of XML for describing mathematical notation and capturing both its structure and content. ... Scalable Vector Graphics (SVG) is a XML markup language for describing two-dimensional vector graphics, both static and animated, and either declarative or scripted. ... Open eBook (or OeB) is the e-book format based on XML format and defined by Open eBook Publication Structure Specification (OeBPS). ... The Text Encoding Initiative (TEI) is a consortium of institutions and research projects which collectively maintains and develops a standard for the representation of texts in digital form. ... XBRL (eXtensible Business Reporting Language) is an emerging XML-based standard to define and exchange business and financial performance information. ...

Generic markup is another term for descriptive markup. Most modern descriptive markup systems structure documents into trees, while also providing some means for embedding cross-references. Because of this, documents can be readily treated as databases, in which the database system is aware of the structure (not "blobs" as in the past). Because they do not have such strict schemas as relational databases, however, they are commonly called "semi-structured databases". In computer science, a tree is a widely-used computer data structure that emulates a tree structure with a set of linked nodes. ... A database is an information set with a regular structure. ... A blob is a collection of binary data stored as a single entity in a database management system. ... A relational database is a database based on the relational model. ...

In the third millennium, great interest has arisen in document structures that are not trees. For example, ancient and sacred literature commonly has a rhetorical or prose structure (stories, pericopes, paragraphs, and so on), as well as a reference structure (books, chapters, verses, lines). Since the boundaries of these units often cross, they cannot readily be encoded using tree-structured markup systems. Among the document modeling systems that support such structures are MECS (developed for encoding the works of Wittgenstein), aspects of the TEI Guidelines, LMNL, and CLIX. A pericope (pur-IC-op-ee) (Greek περικοπη, a cutting-out) in rhetoric is a set of verses which form one coherent unit or thought. ... Ludwig Wittgenstein (1889-1951), pictured here in 1930, made influential contributions to Logic and the philosophy of language, critically examining the task of conventional philosophy and its relation to the nature of language. ... A brand of pre-painted miniatures game by WizKids featuring rotating statistics dials in the base of the figures. ...

A primary virtue of descriptive markup is considered to be its flexibility: if the fragments of text are labeled as to "what they are" as opposed to "how they should be displayed", software may be written to process these fragments in useful ways not anticipated by the designers of the languages. For example, HTML's hyperlinks, originally designed for activation by a human following a link, are also widely used by Web search engines both in discovering new material to index and in estimating the popularity of Web resources.

Descriptive markup also facilitates the simpler task of reformatting a document as needed, because the format specification is not intertwined with the content. For example, italics might be used both for emphasis, and to indicate foreign words. However, if both are merely tagged (presentationally or procedurally) as italic, this ambiguity cannot readily be sorted out. If a decision is later made not to italicize foreign words, there is nothing for it but to review all italic portions and sort them out one by one. However, if the two cases were (descriptively or generically) tagged differently to begin with, either can be reformatted without interfering with the other.

History

The term "markup" is derived from the traditional publishing practice of "marking up" a manuscript, that is, adding symbolic printer's instructions in the margins of a paper manuscript. For centuries, this task was done by specialists known as "markup men" and proofreaders who marked up text to indicate what typeface, style, and size should be applied to each part, and then handed off the manuscript to someone else for the tedious task of typesetting by hand. A familiar example of manual markup symbols still in use is proofreader's marks, which are a subset of larger vocabularies of handwritten markup symbols. A manuscript (Latin manu scriptus, written by hand), strictly speaking, is any written document that is put down by hand, in contrast to being printed or reproduced some other way. ... For other articles which might have the same name, see Print (disambiguation). ... For the origin and evolution of fonts, see History of western typography. ... This article or section is in need of attention from an expert on the subject. ... Proofreading means reading a proof copy of a text in order to detect and correct any errors. ...

GenCode

The idea of "markup languages" was apparently first presented by publishing executive William W. Tunnicliffe at a conference in 1967, although he preferred to call it "generic coding." Tunnicliffe would later lead the development of a standard called GenCode for the publishing industry. Book designer Stanley Fish also published speculation along similar lines in the late 1960s. Brian Reid, in his 1980 dissertation at Carnegie Mellon University, developed the theory and a working implementation of descriptive markup in actual use. However, IBM researcher Charles Goldfarb is more commonly seen today as the "father" of markup languages, because of his work on IBM GML, and then as chair of the International Organization for Standardization committee that developed SGML, the first widely used descriptive markup system. Goldfarb hit upon the basic idea while working on an early project to help a newspaper computerize its workflow, although the published record does not clarify when. He later became familiar with the work of Tunnicliffe and Fish, and heard an early talk by Reid which further sparked his interest. William W. Tunnicliffe (1922? - September 12, 1996) is credited by Charles Goldfarb as being the first person (1967) to articulate the idea of separating the definition of formatting from the structure of content in electronic documents. ... Brian Keith Reid (1949- ) is a computer scientist most famous for developing the Scribe word processing system, the subject of his 1980 doctoral dissertation, for which he received the Association for Computing Machinerys Grace Murray Hopper Award in 1982. ... Carnegie Mellon University is a private research university located in Pittsburgh, Pennsylvania. ... International Business Machines Corporation (known as IBM or Big Blue; NYSE: IBM) is a multinational computer technology and consulting corporation headquartered in Armonk, New York, USA. The company is one of the few information technology companies with a continuous history dating back to the 19th century. ... Charles F. Goldfarb is known as the father of SGML, co-inventor of the concept of markup languages. ... The International Organization for Standardization (ISO) is an international standard-setting body composed of representatives from various national standards bodies. ...

It must be noted that the details of the early history of descriptive markup languages are hotly debated. However, it is clear that the notion was independently discovered several times throughout the 70s (and possibly the late 60s), and became an important practice in the late 80s.^{[citation needed]}

Some early examples of markup languages available outside the publishing industry can be found in typesetting tools on Unix systems such as troff and nroff. In these systems, formatting commands were inserted into the document text so that typesetting software could format the text according to the editor's specifications. It was a trial and error iterative process to get a document printed correctly.^{[citation needed]} Availability of WYSIWYG ("what you see is what you get") publishing software supplanted much use of these languages among casual users, though serious publishing work still uses markup to specify the non-visual structure of texts. Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIXÂ®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... Troff is a document processing system developed by AT&T for the Unix operating system. ... The title given to this article is incorrect due to technical limitations. ... Trial and error is a method for obtaining knowledge, both propositional knowledge and know-how. ... WYSIWYG (IPA Pronunciation [] or []), is an acronym for What You See Is What You Get, used in computing to describe a system in which content during editing appears very similar to the final product. ...

TeX

Another major publishing standard is TeX, created and continuously refined by Donald Knuth in the 1970s and 80s. TeX concentrated on detailed layout of text and font descriptions in order to typeset mathematical books in professional quality. This required Knuth to spend considerable time investigating the art of typesetting. However, TeX requires considerable skill from the user, so that it is mainly used in academia, where it is a de-facto standard in many scientific disciplines. A TeX macro package known as LaTeX provides a descriptive markup system on top of TeX, and is widely used. TeX (IPA: as in Greek, often in English; written with a lowercase e in imitation of the logo) is a typesetting system created by Donald Knuth. ... Donald Ervin Knuth ( or Ka-NOOTH[1], Chinese: [2]) (b. ... This article or section is in need of attention from an expert on the subject. ... Plato is credited with the inception of academia: the body of knowledge, its development and transmission across generations. ... The LaTeX logo, typeset with LaTeX LATEX, written as LaTeX in plain text, is a document markup language and document preparation system for the TeX typesetting program. ...

SGML

The first language to make a clear and clean distinction between structure and presentation was certainly Scribe, developed by Brian Reid and described in his doctoral thesis in 1980.^[1] Scribe was revolutionary in a number of ways, not least that it introduced the idea of styles separated from the marked up document, and of a grammar controlling the usage of descriptive elements. Scribe influenced the development of Generalized Markup Language (later SGML) and is a direct ancestor to HTML and LaTeX. The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ... Brian Keith Reid (1949- ) is a computer scientist most famous for developing the Scribe word processing system, the subject of his 1980 doctoral dissertation, for which he received the Association for Computing Machinerys Grace Murray Hopper Award in 1982. ... For the surname, see Grammer. ... GML GML (Generalized Markup Language) is a set of macros (tags) for the IBM text formatter SCRIPT. SCRIPT is the main component of IBMs Document Composition Facility (DCF). ... The LaTeX logo, typeset with LaTeX LATEX, written as LaTeX in plain text, is a document markup language and document preparation system for the TeX typesetting program. ...

In the early 1980s, the idea that markup should be focused on the structural aspects of a document and leave the visual presentation of that structure to the interpreter led to the creation of SGML. The language was developed by a committee chaired by Goldfarb. It incorporated ideas from many different sources, including Tunnicliffe's project, GenCode. Sharon Adler, Anders Berglund, and James D. Mason were also key members of the SGML committee.

SGML specified a syntax for including the markup in documents, as well as one for separately describing what tags were allowed, and where (the Document Type Definition (DTD) or schema). This allowed authors to create and use any markup they wished, selecting tags that made the most sense to them and were named in their own natural languages. Thus, SGML is properly a meta-language, and many particular markup languages are derived from it. From the late 80s on, most substantial new markup languages have been based on SGML system, including for example TEI and DocBook. SGML was promulgated as an International Standard by International Organization for Standardization, ISO 8879, in 1986. Document Type Definition (DTD), defined slightly differently within the XML and SGML specifications, is one of several SGML and XML schema languages, and is also the term used to describe a document or portion thereof that is authored in the DTD language. ... The word schema comes from the Greek word σχήμα (skhēma) that means shape or more generally plan. ... Metalanguage can refer to: An intermediate step in the compilation/assembly/interpreting process. ... The Text Encoding Initiative (TEI) is a consortium of institutions and research projects which collectively maintains and develops a standard for the representation of texts in digital form. ... DocBook is a markup language for technical documentation, originally intended for authoring technical documents related to computer hardware and software but which can be used for any other sort of documentation. ... The International Organization for Standardization (ISO) is an international standard-setting body composed of representatives from various national standards bodies. ...

SGML found wide acceptance and use in fields with very large-scale documentation requirements. However, it was generally found to be cumbersome and difficult to learn, a side effect of attempting to do too much and be too flexible. For example, SGML made end tags (or start-tags, or even both) optional in certain contexts, because it was thought that markup would be done manually by overworked support staff who would appreciate saving keystrokes. For a proposal for tagging in Wikipedia, see Wikipedia:WikiProject Microformats#MediaWiki issues A tag cloud with terms related to Web 2. ...

HTML

By 1991, it appeared to many that SGML would be limited to commercial and data-based applications while WYSIWYG tools (which stored documents in proprietary binary formats) would suffice for other document processing applications. HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ... WYSIWYG (IPA Pronunciation [] or []), is an acronym for What You See Is What You Get, used in computing to describe a system in which content during editing appears very similar to the final product. ... Word processing, in its now-usual meaning, is the use of a word processor to create documents using computers. ...

The situation changed when Sir Tim Berners-Lee, learning of SGML from co-worker Anders Berglund and others at CERN, used SGML syntax to create HTML. HTML resembles other SGML-based tag languages, although it began as simpler than most and a formal DTD was not developed until later. DeRose^[2] argues that HTML's use of descriptive markup (and SGML in particular) was a major factor in the success of the Web, because of the flexibility and extensibility that it enabled (other factors include the notion of URLs and the free distribution of browsers). HTML is quite likely the most used markup language in the world today. Sir Tim Berners-Lee Sir Tim (Timothy John) Berners-Lee, KBE (TimBL or TBL) (b. ... CERN logo The Organisation europÃ©enne pour la recherche nuclÃ©aire (English: European Organization for Nuclear Research), commonly known as CERN, pronounced (or in French), is the worlds largest particle physics laboratory, situated just northwest of Geneva on the border between France and Switzerland. ... HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ...

However, HTML's status as a markup language is disputed by some computer scientists.^{[citation needed]} The argument for this is that HTML restricts the placement of tags, requiring them to be either fully nested inside of other tags, or the root tag of the document. Because of this, these scientists would suggest instead that HTML is a container language, following a Hierarchical model. In a hierarchical data model, data are organized into a tree-like structure. ...

XML

Another, newer, markup language that is now widely used is XML (Extensible Markup Language). XML was developed by the World Wide Web Consortium, in a committee created and chaired by Jon Bosak. The main purpose of XML was to simplify SGML by focusing on a particular problem — documents on the Internet.^[3] XML remains a meta-language like SGML, allowing users to create any tags needed (hence "extensible") and then describing those tags and their permitted uses. The Extensible Markup Language (XML) is a general-purpose markup language. ... The Extensible Markup Language (XML) is a general-purpose markup language. ... The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web (W3). ... Jon Bosak led the creation of the XML specification at the W3C. Tim Bray, who was one of the editors of the XML specification, has this to say in his note on Bosak in his annotated version of the spec: Jon Bosak is the single person without whose efforts XML...

XML adoption was helped because every XML document is also an SGML document, and existing SGML users and software could switch to XML fairly easily. However, XML eliminated many of the more complex features of SGML, easing learning and implementation (while increasing markup size and reducing readability). Other improvements rectified some SGML problems in international settings, and made it possible to parse and interpret document hierarchy even if no schema is available.

XML was designed primarily for semi-structured environments such as documents and publications. However, it appeared to hit a sweet spot between simplicity and flexibility, and was rapidly adopted for many other uses. XML is now widely used for communicating data between applications. A sweet spot is a place, often numerical as opposed to physical, where a combination of factors suggest a particularly suitable solution. ... A transaction is an agreement, communication, or movement carried out between separate entities or objects. ...

XHTML

Since January 2000 all W3C Recommendations for HTML have been based on XML rather than SGML, using the abbreviation XHTML ('Extensible HyperText Markup Language). The language specification requires that XHTML Web documents must be "well-formed" XML documents – this allows for more rigorous and robust documents while using tags familiar from HTML. The Extensible HyperText Markup Language, or XHTML, is a markup language that has the same depth of expression as HTML, but with a syntax that conforms to XML syntax. ... 2000 : January - February - March - April - May - June - July - August - September - October - November - December Events: January 1- Millennium celebrations take place throughout the world. ... A W3C Recommendation is the final stage of a ratification process of the W3C working group concerning the standard. ... The Extensible HyperText Markup Language, or XHTML, is a markup language that has the same depth of expression as HTML, but with a syntax that conforms to XML syntax. ...

One of the most noticeable differences between HTML and XHTML is the rule that all tags must be closed: 'empty' HTML tags such as <br> must either be 'closed' with a regular end-tag, or replaced by a special form: <br /> (note that there must be a space before the '/' on the end tag as otherwise the tag is not valid SGML). Another is that all attribute values in tags must be quoted. HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ...

Other XML-based applications

Many XML-based applications now exist, including Resource Description Framework (RDF), XForms, DocBook, SOAP and the Web Ontology Language (OWL). For a partial list of these see List of XML markup languages. Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata model but which has come to be used as a general method of modeling information, through a variety of syntax formats. ... XForms is two things: 1. ... DocBook is a markup language for technical documentation, originally intended for authoring technical documents related to computer hardware and software but which can be used for any other sort of documentation. ... Handmade soap Soap is a surfactant used in conjunction with water for washing and cleaning. ... The Web Ontology Language (OWL) is a language for defining and instantiating Web ontologies. ... This page aims to list articles related XML markup languages. ...

Features

A common feature of many markup languages is that they intermix the text of a document with markup instructions in the same data stream or file. Here, for example, is a small section of text marked up in HTML:

The codes enclosed in angle-brackets <like this> are markup instructions (known as tags), while the text between these instructions is the actual text of the document. The codes "h1", "p", and "em" are examples of structural markup, in that they describe the intended purpose or meaning of the text they include. Specifically, "h1" means "this is a first-level heading", "p" means "this is a paragraph", and "em" means "this is an emphasized word". A device reading such structural markup may apply its own rules or styles for presenting it, using larger type, boldface, indentation, or whatever style it prefers. The "i" instruction is an example of presentational markup. It specifies the exact appearance of the text (in this case, the use of an italic typeface) without specifying the reason for that appearance.

The Text Encoding Initiative (TEI) has published extensive guidelines for how to encode texts of interest in the humanities and social sciences, developed through years of international cooperative work. These guidelines are used by countless projects encoding historical documents, the works of particular scholars, periods, or genres, and so on. The Text Encoding Initiative (TEI) is a consortium of institutions and research projects which collectively maintains and develops a standard for the representation of texts in digital form. ...

Alternative usage

While the idea of markup language originated with text documents, there is an increasing usage of markup languages in areas like vector graphics, web services, content syndication, and user interfaces. Most of these are XML applications because it is a clean, well-formatted, and extensible language. The use of XML has also led to the possibility of combining multiple markup languages into a single profile, like XHTML+SMIL and XHTML+MathML+SVG^[4] Example showing effect of vector graphics versus raster graphics. ... The W3C defines a Web service[1] as a software system designed to support interoperable Machine to Machine interaction over a network. ... A typical web feed logo Web syndication is a form of syndication in which a section of a website is made available for other sites to use. ... The user interface is the part of a system exposed to users. ... XHTML+SMIL adds timing and media synchronization support to XHTML pages. ...

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