NAME
xmlparsing - XML Parsing with Coin For Coin 3.0, we added an XML parser
to Coin. This document describes how it can be used for generic
purposes.
Why another XML parser, you might ask? First of all, the XML parser is
actually a third-party parser, expat. Coin needed one, and many Coin-
dependent projects needed one as well. We therefore needed to expose an
API for it. However, integrating a 3rd-party parser into Coin, we can
not expose its API directly, or other projects also using Expat would
get conflicts. We therefore needed to expose the XML API with a unique
API, hence the API you see here. It is based on a XML DOM API we use(d)
in a couple of other projects, but it has been tweaked to fit into Coin
and to be wrapped over Expat (the original implementation just used
flex).
The XML parser is both a streaming parser and a DOM parser. Being a
streaming parser means that documents can be read in without having to
be fully contained in memory. When used as a DOM parser, the whole
document is fully parsed in first, and then inspected by client code by
traversing the DOM. The two modes can actually be mixed arbitrarily if
ending up with a partial DOM sounds useful.
The XML parser has both a C API and a C++ API. The C++ API is just a
wrapper around the C API, and only serves as convenience if you prefer
to read/write C++ code (which is tighter) over more verbose C code.
The C API naming convention may look a bit strange, unless you have
written libraries to be wrapped for scheme/lisp-like languages before.
Then you might be familiar with the convention of suffixing your
functions based on their behaviour/usage meaning. Mutating functions
are suffixed with ’!’, or ’_x’ for (eXclamation point), and predicates
are suffixed with ’?’, or ’_p’ in C.
The simplest way to use the XML parser is to just call
cc_xml_read_file(filename) and then traverse the DOM model through
using cc_xml_doc_get_root(), cc_xml_elt_get_child(), and
cc_xml_elt_get_attr().
See also:
XML related functions and objects, cc_xml_doc, cc_xml_elt,
cc_xml_attr