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<TITLE>OpenSP - XML support</TITLE>
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<H1>XML support</H1>
<H2>Using OpenSP to parse XML</H2>
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To enable OpenSP's support for <A
HREF="http://www.w3.org/TR/1998/REC-xml-19980210">XML 1.0</A>:
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<LI>
Set the <SAMP>SP_CHARSET_FIXED</SAMP> environment variable to <SAMP>YES</SAMP>.
<LI>
Set the <SAMP>SP_ENCODING</SAMP> environment variable to <SAMP>XML</SAMP>.
<LI>
Set the <SAMP>SGML_CATALOG_FILES</SAMP> environment variable to
point to the file <SAMP>pubtext/xml.soc</SAMP>.
<LI>
Use the <SAMP>-wxml</SAMP> option.
<LI>
If the document is not supposed to be valid, use <SAMP>-wno-valid</SAMP>
option.
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<H2>Limitations</H2>
<P>
OpenSP does not enforce the following XML constraints:
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XML constrains processing instructions
with a target matching <CODE>[Xx][Mm][Ll]</CODE>,
both in terms of where they can occur and their content.
<LI>
XML does not allow a parameter separator that is adjacent to a
delimiter to be omitted.
<LI>
XML has constraints on the use of <CODE>&</CODE> in parameter
literals. In SGML terms, XML says that the <b>ero</b> delimiter is
recognized in a parameter literal, and that it must be followed by an
entity reference, but the entity reference is not expanded.
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<P>
Line ends are normalized using SGML conventions to a CR/LF character
pair rather than using the XML convention of a single LF character.
<P>
OpenSP does not enforce XML's rules on not continuing normal processing
after an error. Applications can enforce these if they choose.
<H2>Web SGML Adaptations Annex</H2>
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OpenSP's support for XML is based on <A
HREF="http://www.ornl.gov/sgml/sc34/document/0029.htm">Annex K of ISO
8879</A> (the Web SGML Adaptations Annex).
The following features of Annex K are not yet implemented:
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<SAMP>#IMPLIED</SAMP> document type name
<LI>
<SAMP>#ALL</SAMP> and <SAMP>#IMPLICIT</SAMP> in model groups and exceptions
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