| catalogResolve {XML} | R Documentation |
XML parsers use a catalog to map generic system and public addresses
to actual local files or potentially different remote files.
We can use a catalog to map a reference such as
http://www.omegahat.org/XSL/ to a particular
directory on our local machine and then not have to
modify any of the documents if we move the local files to another
directory, e.g. install a new version in an alternate directory.
This function provides a mechanism to query the catalog to resolve a URI, PUBLIC or SYSTEM identifier.
catalogResolve(id, type = "uri", debug = FALSE)
id |
the name of the (generic) element to be resolved |
type |
a string, specifying whether the lookup is for a uri, system or public element |
debug |
logical value indicating whether to turn on debugging
output written to the console (TRUE) or not (FALSE). |
A character vector. If the element was resolved, the single element is the resolved value. Otherwise, the character vector will contain no elements.
Duncan Temple Lang
http://www.xmlsoft.org http://www.sagehill.net/docbookxsl/Catalogs.html provides a short, succinct tutorial on catalogs.
Sys.putenv("XML_CATALOG_FILES" = system.file("exampleData", "catalog.xml", package = "XML"))
catalogResolve("-//OASIS//DTD DocBook XML V4.4//EN", "public")
catalogResolve("http://www.omegahat.org/XSL/foo.xsl")
catalogResolve("http://www.omegahat.org/XSL/article.xsl", "uri")
catalogResolve("http://www.omegahat.org/XSL/math.xsl", "uri")
# This one does not resolve anything, returning an empty value.
catalogResolve("http://www.oasis-open.org/docbook/xml/4.1.2/foo.xsl", "uri")