7.1 The Standards
The terms XSL and XSLT,
while similar, do not refer to the same W3C specification. XSL, the
Extensible Stylesheet Language itself, is simply a language for
expressing stylesheets. A stylesheet is a document that controls the
presentation of an XML document of a given type. XSL can be thought
of as analogous to Cascading Style Sheets (CSS); in fact, XSL shares
most of its properties with CSS2, although they have different
syntaxes.
XSLT, the XSL Transformation language, is a subset of XSL that was
originally designed to perform transformations of XML elements into
complex styles, such as nested tables and indexes. XSLT is designed
to be usable independent of XSL; however, its use is constrained by
its design as a transformation language for the sorts of tasks
required by XSL.
Despite the differences,
you'll often see the acronyms XSL and XSLT used
interchangeably. Unless the speaker is describing complete formatting
systems, odds are good that XSL is probably actually a mis-cited
reference to XSLT. To add to the confusion, Microsoft has chosen to
call the .NET XSLT namespace System.Xml.Xsl.
XSL-FO, or XSL Formatting Objects,
provides additional, more complex formatting for XML content.
However, Microsoft does not implement any specific XSL-FO
functionality in .NET, so it is outside the scope of this chapter. If
you're interested in learning about XSL-FO, you
should look into one of the available books about it, such as
XSL-FO (O'Reilly) or
Definitive XSL-FO (Prentice Hall).
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