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Re: gEDA-user: Attribute Net (without pin assignment) - for Power and Port Symbols
On Tue, Apr 12, 2011 at 04:31:03PM +0100, Peter Clifton wrote:
> This is a really neat idea..
>
> P pin number ":1" doesn't really matter, it is just a way of referring
> to a particular pin. If we could reference by other means, that would
> also be cool. I'm thinking of some kind of "id=..." attribute like CSS /
> HTML / SVG would use to refer to other elements.
>
> As someone who's just ranted against lots of magic special cases.. how
> would people feel to a primitive "id=..." attribute which is handled by
> API to look up and element's ID. We could make the code DEFAULT to
> looking up pinnumber= or pinseq= for pins (if an id=... doesn't exist),
> so the new syntax could key off id=, not pinnumber= or ....
So we are more or less looking at a simplified hierarchical path syntax, where
elements without explicit id= provide default id based on the type and other
attributes?
Examples:
U1.1.net=Vcc (global attribute, pinnumber assumed for 1)
1.net=Vcc (attribute attached to U1)
D1.A.net=Vcc (global, pinlabel assumed for A)
Same could be specified in hierarchical design and would possibly solve the
problem of different values in different instances of subcircuits.
We'd have to work a bit on the syntax, precedence, resolution rules and how to
refer to target attribute (in the above examples net would need to be a keyword).
From that there's only a small step towards referring to arbitrary values in
expressions (to specify component values etc).
--
Krzysztof KoÅciuszkiewicz
"Simplicity is the ultimate sophistication" -- Leonardo da Vinci
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