The term ''markup language'' usually refers to a set of
characters that a writer inserts into a file of text to indicate
some sort of special meaning or action to be taken at a point in
a documentation.

For example, one type of markup might have semantic meaning whereby a text
has notations indicating ''here is the title of the document'',
''here is begins the next chapter'', ''here is the beginning of
a new paragraph'', etc.

A very common type of markup is presentation markup.  This
is the type of markup we use on this wiki.  With presentation
markup, you indicate what special actions should be taken during
transformation of the text from ''raw'' text to the form presented
to the user.  Here on the wiki, we can
   * mark words as ''italic'' (surround then with double apostrophes)
   * mark words as '''bold'''  (surround them with triple apostrophes)
   * insert horizontal rules (four dashes in a line only)
   * create bulleted lists (start line with 3 spaces, asterisk, space, then your text)

and more.

Typically, if one has a semantic markup, one also has some sort of
means to also transform the semantical parsed text into a preferred
presentation format.  However, the opposite is not often true - if
one only has presentation markup, it is quite hard to generate an
accurate semantical tree of the document, unless the user takes
great care to use presentation and content in such a way that one
can somehow derive semantical meaning from the text.
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These distinctions are sometimes summarized as being between ''procedural markup''
and ''declarative markup''.
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See [Simple Markup] for a simple presentation markup language.
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[Category Glossary] |
[Category Documentation]