![]() The organization of XDMF begins with the Xdmf element. The text in double quotes is substituted for the entity reference &cellDimsZXY (note the trailing semicolon) whenever the parser encounters the latter in the remaining part of the document. In addition to Xinclude and XPath, which allow for references to data outside the actual XMDF, XML's basic substitution mechanism of entities can be used to render the XDMF document more readable.įor instance, once an entity alias has been defined in the header via While there exists an Xdmf DTD and a Schema they are only necessary for validating parsers.įor performance reasons, validation is typically disabled. So a minimal (empty) XDMF XML file would be: The first grid with an attribute Name which has a value of "Copper Plate" Plate"]Īll valid XDMF must appear between the and the tags. This allows for elements in the XML document and the API to reference specific elements in a document. Then anywhere within the Xdmf element, xi:include will pull in the URL. This means that with XInclude the included file could be well formed XML or perhaps a flat text file of values. Verifying that the provided XML is well formed and/or valid are functions typically performed by the XML parser.Īs opposed to entity references in XML (see below), XInclude allows for the inclusion of files that are not well formed XML. XML is said to be "valid" if it conforms to the Schema or DTD defined at the head of the document.įor example, the schema might specify that element type A can contain element B but not element C. That means all of the quotes match, all elements have end elements, etc. XML is said to be "well formed" if it is syntactically correct. This tree can be queried, modified, and then "serialized" back into XML. The XML parser in the XDMF API parses the XML file and builds a tree structure in memory to describe its contents. ![]() ![]() Optionally there can be several "Name=Value" pairs which convey additional information.īetween the and the there can be other pairs and/or character data (CData).ĬData is typically where the values are stored like the actual text in an HTML document. In XDMF the element is the most important component.Īdditionally XDMF takes advantage of two major extensions to XML: XInclude and XPath.Įach element begins with a and ends with a. It it case sensitive and is made of three major components: elements, entities, and processing information. Without going into too much detail, XDMF views XML as a "personalized HTML" with some special rules. The XDMF API takes advantage of the libxml2 parser to provide the necessary functionality. There are numerous open source parsers available for XML. The eXtensible Markup Language (XML) format is widely used for many purposes and is well documented at many sites.
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