XML
Mechanism to describe markup languages and conventions
Character set definition + tag format specification +
document type definition (DTD)
Based on a descriptive definition
Several features to reduce size of markup (e.g., tag
minimization, shortrefs)
Applications: CALS, AAP, TEI, HTML
PAT regions
(search)
Lector
(display)
Goedel
(structured query)
MAD (interprocess communication)
Goals:
SGML variant for a variety of applications operating over the
Internet
formally defined, simple to process, human readable (but not
necessarily terse)
no features that are optionally implemented
XML processor vs. XML application
Data components:
markup vocabulary: elements, attributes
"start tag ... content ... end tag" (<name type="first">Frank</name>) vs. "empty tag" (<name/>)
character entity references (<)
vs. character references (<
or <)
white space, parsed and unparsed character data, entity
references
comments <!-- ... -->, processing instructions <? ... ?>
XML declaration: <?xml version="1.0"?>
Example: Melton and Buxton's Movies, Michael Ley's DBLP (not viewable from Firefox)
Markup declarations using Document Type Definition (DTD):
internal vs. external
root document type
elements
attribute lists (including IDs and IDREFs)
notations
entities
Conformance:
well-formed:
syntactically correct tags, matching
tags, nested elements, all entities declared
valid:
well-formed + DTD + doctype matches DTD, unique IDs, no dangling IDREFs
Example: Movies DTD, DBLP DTD
W3C specifications
Stages: Working draft, candidate recommendation , proposed recommendation, recommendation
XML suite of specifications:
XML Transducers |
XML Applications |
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CSS, XSL |
Web Publishing |
Semantic Web |
Web Communications |
Non-textual Data |
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XSLT |
XHTML |
RDF |
CC/PP |
MathML |
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XQuery |
XHTML-Print |
RDF Schema |
SOAP |
SMIL |
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Canonical XML |
XML Events |
GRDDL |
P3P, APPEL |
SMIL Animation |
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XInclude |
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OWL |
XML-Signature |
SVG |
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XML Encryption |
Ruby Annotation |
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XKMS |
VoiceXML, SSML |
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EARL |
CCXML |
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REX |
EMMA |
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SML |
InkML |
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Timed Text |
XML Accessories |
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XML Names, XML Schema, XPath, XLink, XML Base, XPointer, XBL, ITS, XML Stylesheet, xml:id |
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XML |
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Querying XML,
Chapters 1, 16, B.2
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