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	Mon, 12 Oct 2015 13:06:50 -0700 (PDT)
Date:	Mon, 12 Oct 2015 22:06:49 +0200
From:	"Nicklas Karlsson (nicklas DOT karlsson17 AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] A lesson from gnet-makefile
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> Folks,
> 
> I had thought that the lack of a way to access attributes other than netname= on a net via gnetlist was a serious barrier to the back end writer. However, for gnet-makefile.scm  I find myself using the attributes of the attached symbols as a rich source of information about the net. Is this perhaps the best approach anyway?
> 
> Nets in a schematic represent collapsed topology, not geometry or even the complete topology. The layout system is responsible for these things. A schematic doesn’t capture the relationships between the net segments. Some paths on a net may carry large currents, but others may not. Pairs of nets may represent balanced transmission lines.
> 
> But, suppose instead that we had a pin attribute that said “this pin may draw three amps”. The netlister could then deduce which paths on a net need extra conductor.
> 
> Suppose a resistor had an attribute that meant  “100 ohm shunt terminator”. Imagine a component with a pair of pins identified by an attribute as a differential input. Put them on the same pair of nets, and the netlister could deduce that the pair is a balanced transmission line and the the resistor needs to be close to the input.
> 
> Of course, we’d need a layout program that could accept this info.
> 
> John Doty              Noqsi Aerospace, Ltd.
> http://www.noqsi.com/
> jpd AT noqsi DOT com

As I understand it you want to assign attributes to pins instead of nets.

A net is only allowed to have one driver and will get the voltage of the driving pin and from this voltage a suitable clearance may be selected. For current it will be the other ends. It might work but I still think net names are useful sometimes, maybe it would be useful to use the driving pin to assign the net name, if this is simple to implement I guess it would be worth a try.

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