gEDA: symbol libraries and attributes

[Jonathan Hanson <hanson-at-NOSPAMphgrav_dot_phys_dot_lsu_dot_edu>]

I'm running into an issue with symbols and gschem.

I think gEDA and friends are a good idea, and I'm going to attempt to 
make the switch from closed-source packages.  However, one big glaring 
issue I've noticed in gEDA is the state of the symbol library.  The 
organization is pretty bad.  Also, according to the tutorials I've read 
for capturing a schematic and then laying it out as a PCB, you have to 
hand edit attributes like 'footprint' in several of the symbols after 
dropping them into the schematic.  This obviously isn't the best way to 
have things set up; it would be better if these symbols were already 
loaded with the useful information, even if that means a larger library 
to choose from.

In addition, in Electronics Workbench (the closed package I'm most 
familiar with), I really liked the idea of having resistor and capacitor 
symbols available with the resistance or capacitance values already set 
to standard commercially available values.  I know this is just a 
preference, but I thought it was convenient and worth the increase in 
symbol library size.  Rather than drop in a generic resistor and then 
edit its attributes, you can just pick the resistor from the symbol 
library with the required value and move on without editing anything.

Anyway, I figured I would just build my own custom symbol library to my 
own spec, since all I use are basic passive parts, a few transistors and 
some diodes.  It shouldn't be too hard to just build symbols as I need 
them.  I read through the guide at
http://www.geda.seul.org/docs/current/fileformats/index.html detailing 
how to build a symbol, and starting building a 2N5551 transistor model.

Now the problem I have is in the visibility of attributes.  I intend to 
have all the useful attributes filled in (stuff like documentation and 
footprint), but these aren't values that need to be visible on the 
schematic once the device is inserted into the schematic.  The problem 
is, a section of the .sym file like:

T 1400 0 8 10 0 1 0 0 1
footprint=TO92

gets ignored by gschem when the symbol is inserted.  Checking the 
attributes of the symbol only shows attributes from the .sym file that 
were marked as visible.  The sixth field being set to '0' is supposed to 
make the following attribute invisible, but instead, gschem just 
considers it something to be thrown away.  Saving the file that the 
symbol was imported into and checking it with a text editor confirms 
that anything that wasn't marked 'visible' is stripped off a symbol.

There're lots of attributes that need to be kept associated with the 
symbol in the file, but not necessarily displayed on the schematic.  
Would it be possible to modify gschem so that attributes in the .sym 
file that are marked as invisible still get stored in the .sch file, but 
just stay marked invisible so as not to appear on the schematic?

On the previous note: I don't know what the protocol is for building new 
symbol sets, but once I'm done with the resistor and capacitor sets in 
standard values, I'd be happy to tar them up and submit them.  Would 
there be any interest in them?

Anyway, thanks for all the fine work, and thanks in advance for any 
advice I can get here.
  - Jonathan Hanson
    Louisiana State University
    Department of Physics and Astronomy