gEDA-dev: [pcb] attributes

[DJ Delorie]

> This leads me to a tangential riff on the following question: Now
> that both gschem and PCB have them, what is the purpose of these
> unattached attributes?

My primary motivation was for metadata - authorship, copyright,
pointers to web pages, etc.  PCB has no other way of recording
these in a way that gets preserved across load/save.

> 2.  They can hold information pertainent to the *tool*.  For
> example, you can hold the last zoom setting of your gschem session,
> the column widths and order for gattrib, etc.

That too, if you want.  I figured other tools that process pcb files
would want some way of recording their info in there, for example, an
RF analyzer would store its rule settings in there.  My guideline was
"I don't know what they'll use it for" ;-)

I'm still open to suggestions on where in the file it should be
placed.  I put it after the symbol table only because that makes it
easier to parse flexibly.  However, I also thought of making the
parser not care about the order of things in the pcb file, so that
they could be spit out earler (i.e. near the top) while still being
allowed elsewhere in the file.

> Therefore, my question: Is the intent of an unattached attribute to
> hold tool-related meta information?  Is this what other programs do?

When the tool-related meta information is (potentially)
board-specific, yes.