Re: gEDA-user: Driving the netlist from PCB (instead of gschem)

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Mon, 2008-09-29 at 23:31 -0400, DJ Delorie wrote:
> 
> 
> The XML parsing libraries are huge and have dependencies, in order to
> support the large degree of flexibility that XML offers.  We don't
> need all that.  It's overkill for us, esp since we already have an
> xml-like parser that's much simpler and very small.

ldd /usr/lib/libxml2.so.2.6.32
	linux-gate.so.1 =>  (0xb80c0000)
	libdl.so.2 => /lib/tls/i686/cmov/libdl.so.2 (0xb7f5b000)
	libz.so.1 => /usr/lib/libz.so.1 (0xb7f45000)
	libm.so.6 => /lib/tls/i686/cmov/libm.so.6 (0xb7f1e000)
	libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0xb7dc0000)
	/lib/ld-linux.so.2 (0xb80c1000)

The one non-standard C library dependancy there is zlib, and if we have
png support on a system, we probably have zlib.

Admittedly, it is fairly large:

ls -lh /usr/lib/libxml2.so.2.6.32 
-rw-r--r-- 1 root root 1.3M 2008-09-25 13:36 /usr/lib/libxml2.so.2.6.32

(For comparison, gtk-x11 is 3.7M, Lesstif libXM.so is 1.3M)

Since it is portable, and externally maintained, the only reason not to
consider a library like this would be depending on how "maintained" it
is, and how frequently it is going to break ABI.


Some more important questions:

Is the format expressive / extensible enough for what we want? If so, we
can at least learn from it's design.

Is there any direct benefit to supporting it (as is) as a native format?
If "the industry" support reading / writing it, then perhaps the answer
is yes - otherwise we need a native file format, + an importer /
exporter for this one.

(NB: We can always extend an XML based format with our own namespace,
such as inkscape does with SVGs).

Could we support a look-alike syntax without being truly XML? (There is
probably a lot of XML overheard which isn't even used). (If people are
dead against depending on an XML parser.)

Could we translitteate the guts of it into a non-XML, more line-based
format? (Again, if people are dead-against XML for some or other
reason.)

Best wishes,

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)



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