Validating xml with perl
It uses the XPath syntax to define a series of rules that should or should not be true about a given document's structure.Those rules, and the context in which they are evaluated, can be as coarse or as finely-grained as the task at hand requires.Example 22-7 is a DTD for the element didn't follow the DTD, but it couldn't tell us precisely what it violated in the DTD or how.At the time of this writing, you must use XML:: Xerces to validate while using SAX, or to validate against W3C Schema.There are W3C Schemas, but there, too, the entire model must be described, and the technology itself seems a bit biased toward the stricter "data transfer" uses of XML rather the looser models that characterize human communication.DTDs and W3C Schemas have their place, but the learning curve involved in getting it right in order provide a useful level of content validation make their use for most applications impractical. Created by Rick Jelliffe, Schematron is a simple XML application language designed to make validating the structures of XML documents as straightforward and painless as possible.This ensures that any well-formedness errors encountered can also be captured cleanly and sent to the user without causing a server error.
Michael, XML:: Parser has all the workings of a validating parser, and libxml-enno includes a parser that will validate against a DTD, XML:: Parser:: Checker I think, someone will correct me if I'm wrong.
With the exception of XHTML, XML languages are completely foreign to HTML browsers.
You may get a nice colorized tree representing an entire XML document in some, but that is a far cry from the "if it renders correctly here, it will render correctly most anywhere" that goes along with checking HTML markup in an HTML browser.
Both of these features (and Relax NG validation) are planned for XML:: Lib XML, but weren't available at the time of printing. Always validating raises an error if the file does not have a DTD or Schema.
Auto raises an error only if the file has a DTD or Schema, but it fails to validate against that DTD or Schema.