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Re: gEDA-user: gschem: directly connecting two nets?

On Jan 24, 2011, at 5:51 AM, Kai-Martin Knaak wrote:

> Stephan Boettcher wrote:
>> You need to invent some 2-pin symbol with some special attributes, and
>> teach the pcb gnetlist backend(s) to interpret those attributes
>                                ^^^
> If there is a way to mark two net-names as physically the same net,
> then each and every backend should act accordingly.

By default, yes, I agree completely.

> It would be an 
> invitation for nasty surprises if some back-ends would support the 
> fusion and others don't. This calls for an interpretation by the 
> frontend. 

The problem is that each downstream tool potentially has its own model of connectivity, so the default model in gnetlist must address the "lowest common denominator" here. I think that would require that gnetlist simply merge the nets, choosing a common name. But that's probably not good enough for users of specific tools with advanced capabilities.

Therefore, these semantics should not be in the front-end. They should be in the middle layer (gnetlist.scm), where a plug-in or back-end can modify the semantics as needed for the downstream tool. Putting them in the front-end will case trouble similar to that we now experience with slotting, where the front-end model doesn't fit simulation flows.

John Doty              Noqsi Aerospace, Ltd.

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