Re: gEDA-user: More strange ideas: Start PCB layout from symbols view

[John Doty <jpd@xxxxxxxxx>]

On Nov 25, 2009, at 3:39 PM, Dan McMahill wrote:

> Net probing won't work because gschem doesn't understand anything  
> about
> connectivity.

Which model of connectivity should it understand? There isn't just  
one. And if you implement one model in the gschem core, it will  
interfere with the possibility of implementing others.

>   That's also why we can't have a click-to plot interface
> for simulators.  Well that and because we don't have a consistent  
> way of
> dealing with hierarchy from *inside* the tool.

Which model of hierarchy should it understand? Does that model fit  
every design flow?

>   I'm told having gschem
> being graphical only is a good thing.

It is. Consider TeX. Should TeX understand document structure? Which  
model of document structure? It's a *good* thing that TeX only  
understands typesetting, and is extremely script-friendly. If TeX  
understood how to structure a document for, say, one of the IEEE  
journals, it would be a mess getting it to work with AIP or AMS  
styles. And making it work with a non-european language would be even  
worse. But take TeX, add in the LaTeX macros, a class file, a style  
file, maybe some others, and you can format an article for whatever  
English-language journal you're publishing in. Or a book. Or a memo.  
Or you can choose a different macro package as a foundation for some  
other purpose.

One consequence of this excellent design is that TeX is extremely  
stable and bug-free.

Now, gEDA's design isn't nearly as clean as TeX plus LaTeX plus all  
the other stuff. Still, it's *much* better the competition, and can  
be improved. Unfortunately, there's a lot of pressure to make it  
dirtier.

The criticisms at http://ricardo.ecn.wfu.edu/~cottrell/wp.html apply  
to the usual sweet, low-productivity EDA packages (but don't take  
them too literally: EDA is different from document preparation in  
some ways).

What limitations in the Scheme API prevent you from coding a set of  
procedures that implement the particular model of connectivity you  
are interested in?

One place where gEDA is really special is the gnetlist Scheme API,  
which enables gschem to feed a wide variety of downstream flows.  
Rather than changing gEDA into just another sweet, low productivity  
EDA application, we need to build on that strength.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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