Re: gEDA-user: multiple attributes

[John Doty <jpd@xxxxxxxxx>]

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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