Re: [xml] code generation for C++

[Dave Malcolm <david davemalcolm demon co uk>]

On Thu, 2003-11-20 at 01:34, William Brodie-Tyrrell wrote:
> (warning: xml n00b)

IIRC, the xmlroff project at SourceForge had something like this, though
it generates GObjects in C, rather than C++ classes.

In addition, I've hacked up something that does something a bit like
this, though mine is for C, and you have to manually describe the
doctype using a custom set of C preprocessor macros.

It lives inside conglomerate/src in GNOME's CVS; a set of "gxx"
headers.  There are several headers, you #include one, then #include a
header containing DTD <-> C struct mappings, then repeat with a
different header.  One header generates a loader from XML to C, another
generates a saver from C to XML, and another generates prototypes.

It's an evil bit of hackery, and only does what I need so far, but it
saves tediously writing it all by hand and has fixed some bugs for me.

Please let me know if you find other alternatives.

> Can anyone point me at a package that will generate c++ headers and code to
> represent (and load using libxml2) a data structure defined by a DTD?  I
> hacked one up in Perl but its parser is extremely brain-dead and so supports
> only a very limited subset of possible DTDs (it can't handle much more than
> the following example).
>
> I want it to be able to take a DTD like this:
>
> <!ELEMENT a (b,c*)>
> <!ATTLIST a
>       name CDATA #REQUIRED
>       place CDATA #REQUIRED
>       >
> <!ELEMENT b EMPTY>
> <!ATTLIST b
>       param (false|true) "false">
> <!ELEMENT c (#PCDATA)>
>
> and generate classes for a, b & c, eg:
>
> class xml_mydtd_a {
> public:
>       xml_mydtd_a(xmlDocPtr, xmlNodePtr);
>       virtual ~xml_mydtd_a();
>
>       xml_mydtd_b *b;
>       std::vector<xml_mydtd_c *> c;
>       std::string name;
>       std::string place;
> };
>
> class xml_mydtd_b {
> public:
>       xml_mydtd_b(xmlDocPtr, xmlNodePtr);
>       virtual ~xml_mydtd_b();
>
>       enum param_ENUM {
>               param_false,
>               param_true
>       } param;
> };
>
> The generated code should be able to load each of those object types into
> instances of the appropriate classes, allowing me to access them sensibly:
>
> xmlDocPtr doc = xmlParseFile(docname);
> xmlNodePtr cur = xmlDocGetRootElement(doc);
> xml_mydtd_a a = new xml_mydtd_a(doc, cur);
>
> cout << a->name << " at " << a->place << " has b.param = " << a->b->param;
> for(size_t i=0;i<a->c.size();++i)
>       cout << " c[" << i << "] = " << a->c[i]->xmltext;
> delete a;
>
> you get the idea, bindings.  Does such a thing exist outside of my ratty
> little script?  I had a look at gdome but it doesn't appear to do what I want.  
> I get the impression that Quick and Zeus could be the right thing, but this is
> not for a Java project.
>
> Is it possible to feed a DTD to XSLT and use it to generate C++ instead of
> HTML?
>
>
> William Brodie-Tyrrell
>
> --
> Moderation in all things, particularly moderation.
>
> <wfbrodie smug adelaide edu au>
> http://www.cs.adelaide.edu.au/~william
>
>
>
>
>
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-- 
David Malcolm
www.conglomerate.org