Download parametrics editors for structured documents

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2. The markup of structured documents
and attributes. The differences between the two standards regard the SGML
declaration, that in XML is substituted by the XML own declaration, and
the character set, because XML adopts unicode [US91].
Like SGML, valid XML documents must pass two kinds of validation, the
well-formed validation and the schema validation. The well-formed validation is a kind of syntax validation. For example, it ensures that the document
has a unique root container and that all elements are formed by an opening
tag and a closing tag. The schema validation checks if the document follows the rules that are defined in the schema referred by its document type
declaration. The schema of XML documents can be created using different
technologies such as DTD, XML Schema [Tho04, BMC+ 04], RELAX NG
[CM01], Schematron [Jel01] and others.
XML is nowadays the most used descriptive markup language and it is
used to markup a large variety of documents ranging from the documents
that describe user interfaces
16
to the documents that express actions within
business processes 17 , but it is especially suitable for the markup of text-based
resources.
2.4
XML for the markup of text-based resources
In this chapter we have seen that a structured document, both a procedural one and a text-based one, is a resource formed at least by a logical
structure, a human readable content and some other background information usually referred as metadata. Earlier in section 2.1 I gave a definition
of logical structure, that must be intended as the description of the objects
forming the document and the relations between them. The content of a
textual resource is obviously the readable text inside it and the metadata are
16
The XML User Interface Language, is a markup language developed by Mozilla, whose
aim is creating user interfaces of applications like the Firefox web browser.
17
The Business Process Execution Language is an OASIS standard executable language
that enables users to describe business process activities.