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Re: gEDA-user: multiple attributes

On Jan 5, 2011, at 9:56 AM, Stephan Boettcher wrote:

> John Doty <jpd@xxxxxxxxx> writes:
>> I'd prefer a spice-prototype attribute, which would allow us to avoid many of the difficulties without a confusing proliferation of attributes. For the symbol nmos-3.sym, a suitable prototype might be:
>> M? #D #G #S #S $model-name L= W= AS= AD= PS= PD= M=
>> We can yell at each other about syntax, but I think the basic idea is sound. Right now, spice-sdb is essentially reduced to guessing what the symbol represents. It can't always tell reliably (it's been know to decide my flip-flops are diodes!). There isn't generally one right answer: with a different kind of model (subcircuit), the prototype for nmos-3.sym might be:
>> X? #D #G #S $model-name
>> Suggested syntax:
>> First characters up to the "?" are the device prefix.
>> #x means the net attached to pinnumber x.
>> %x means the net attached to pinseq x.
>> `x means the net attached to pinlabel x.
>> $x means the value of attribute x.
>> x= means an optional x=value string to be emitted only if the x attribute is present.
> Same overloading, just sperad out, I don't like that.

Well, it's not quite the same, because the semantics are in the user's control here. The alternative is a confusing proliferation of extra attributes. I don't know that there's a perfect answer.

> Is this too verbose?
> M? #{pinlabel=D} #{pinlabel=G} #{pinlabel=S} #{pinlabel=S} ${model-name} L={length} W={width} AS= AD= PS= PD= M= 

Yes, I think it is. Also note that we've for many years had l=, w=, m=, etc. as special attributes in both SPICE back ends. Unfortunately, it isn't documented, and the case sensitivity always trips me up (as it did above).

John Doty              Noqsi Aerospace, Ltd.

This message contains technical discussion involving difficult issues. No personal disrespect or malice is intended. If you perceive such, your perception is simply wrong. I'm a busy person, and in my business "go along to get along" causes mission failures and sometimes kills people, so I tend to be a bit blunt.

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