Markup language

A markup language (English markup language, ML ) is used to describe the contents of a document format and partly to the description of the process, which is needed to process this data. Originally the awards were in the text as instructions for the typesetters in the print set, but were with the advancement in typography for digital texts from complex languages ​​.

• 3.1 Descriptive Markup Language
• 3.2 Lightweight Markup Language
• 3.3 Procedural Markup Language
• 3.4 programming language

History

The structural features of a text can be "recognized" by typestyle as highlighting in bold or italics, footnotes, references, paragraphs, headings. Listed such structures were previously performed by text Awards ( markup ), originally - handwritten entered on a manuscript - formatting instructions for the typesetters were.

Operation

In markup languages ​​properties, affiliations and procedures of specific words, sentences and paragraphs ( markup elements ) of a text or a set of data are described and assigned, usually by them with distinction elements - be marked - also called tags.

The source text is usually in ASCII or Unicode, UTF- 8 usually written. Often, the language also provides the ability to describe characters, usually by means of a numerical assignment ( Unicode) or by designation, for example, \ mu for μ in LaTeX and HTML μ.

Examples

• Point 1
• Point 2
• Point 3

• item 1
• item 2
• item 3

  \ begin { itemize} \ item item 1 \ item item 2 \ item item 3 \ end { itemize}

  * Point 1 * Point 2 * Point 3

  Distinction and demarcation

  In the markup languages ​​is now roughly divided into languages ​​to pure description, Descriptive Markup Language (DML ) and procedural markup language, Procedural Markup Language (PML ).

  With the pure description languages ​​describe the information, ie the physical and logical structure of a document ( neudeutsch: Layout ) and the semantics of the elements, in contrast to the procedural markup languages ​​, which the presentation of documents - or, among other things on the screen in the web browser for printers - describe.

  Descriptive Markup Language

  Among the pure description languages ​​include those defined in SGML or XML languages ​​HTML, DocBook, TEI, MathML, WML, SVG and XAML.

  Lightweight Markup Language

  Most documents for final presentation in a common markup language such as HTML or XHTML are converted on the server side.

  Classic markup languages ​​that can represent as many and accurate details are usually generated automatically by scripting languages, and do not necessarily have to be used by people directly. But must content of people are written manually, or even read, so they can be displayed graphically using either WYSIWYG or represented directly by simple markup languages ​​. Unlike WYSIWYG text shall not be processed for writing and reading.

  Simplified markup language use, in contrast to classical

  • No detailed tags, such as HTML page , but few unused strings (for example, [ [ page ]]) in order to increase the readability
  • If possible no compelling conclusion as SGML elements by closing tags
  • For use of line breaks or spaces as delimiters

  So an asterisk ( *) at the beginning of a line is a list item and is only shown as a typographic bullet while compiling. This notation is to native HTML (

• text ) shorter. However, this method is not entirely clear, because another function of the asterisk to denote a footnote in conflict here. Other functions within a simplified markup language cause such errors. In some simplified markup languages ​​a bold written text begins with an asterisk ( * loud * I call for help ), which at the beginning of the line (* sound * I call for help ) with the representation will collide for a list entry.

  Apart from purely logical distinction, such as headings and typestyle as pure fat, other functions can be fulfilled

  • Hyperlinks
  • Tags for additional award of a data set with additional information and categorization.
  • Include with transclusions parts of other documents by reference.

  Simplified markup languages ​​have always been used in a purely text-based systems (such as readme or e- mails) to display Hervorherbungen like italic, bold, without these being further converted. Most markup languages ​​have formed in the use of different software, there are few standardized or uniform solutions, although the functions are similar often.

  Procedural Markup Language

  The performing of page description languages ​​such as the typesetting system TeX and LaTeX or ConTeXt its macro packages, you can weitläufigst among the markup languages ​​. Here, however, both properties of the pure description languages ​​as well as the procedural markup languages ​​are used, as is the case with the page description languages ​​for PDF and PostScript.

  Programming language

  However, the distinction is sometimes very difficult, as for example in the PostScript language also properties of programming languages ​​are used. To display a Lissajous figure in PostScript must be so, for example, not be included in a segment list all edges of the graph, as these can also be generated based on a programmed algorithm at runtime. However, the objective is a descriptive data labeling, but this is generated dynamically at runtime from a procedural precursor under certain circumstances. The demarcation of programming languages ​​is fluent in this case because, as these have all markup languages, a syntax, a grammar and a semantics, but no sufficient conditions are used to define a programming language. A programming language is different from a pure markup language by the elements of sequence, iteration and selection.