gEDA-dev: Embellishing light symbols with heavy attributes

[Bernd Jendrissek]

Hi,

I would like some guinea pigs to check out my slotting / heavy-fying
mechanism and tell me what they think of it.  It allows you to
separate your library of "light" symbols from your library of "heavy"
orderable-component symbols.

The changes to the libgeda + gschem sources are too many to
mention here.  In short, the user-visible new features are:

* A new dialog: the Slot Chooser.  It allows you to associate a light
  symbol with any of the available slots in heavy components in your
  schematic.  It also supports arbitrary other actions through a
  gschemrc-defined scheme function.  The idea is to be able to query
  the component library for as-yet-unplaced components that have
  slots that support the selected light symbol.

* Another new dialog: the Slots Editor [ugh, overloaded name].  It
  allows you to edit the slot objects (OBJ_SLOT, 'S') in a heavy symbol,
  so you don't have to do it with vi.  I was too tired to implement all
  the buttons; activating a row in the tree view does work however.

* libgeda "inherits" attributes from slot owners into light symbols, so
  gnetlist still works even though the heavy attributes aren't *really*
  in the symbol it thinks it's looking at.

How to try it out:

1. Clone my geda fork from git://repo.or.cz/geda-gaf/berndj.git

2. Rebuild libgeda, gschem, and symbols.  For symbols, you need to
   ./config.status --recheck && make [install].  My dialogs use libglade
   if it's available, but should fall back to the generated C code if it isn't.

3. Copy system-gschemrc to your ~/.gEDA/, or just let "make install"
   put it where it needs to be if you choose.

4. Open examples/random_circuits/common-emitter.sch and follow
   the instructions on the schematic.  Also open
symbols/transistor/2N3904-heavy.sym
   and edit the slots it has (e + shift-T, or Edit > Edit Slots); double click
   on the single row and add heavy attributes.

libgeda will be quite noisy on the console as it spews some debugging
info.  I'll kill that eventually.  I also expect valgrind to be somewhat
angry about leaked objects and the like.

Thanks in advance for your feedback.