Re: gEDA-user: Light? Heavy? Reuse...

[DJ Delorie <dj@xxxxxxxxxxx>]

> > Certainly a good idea, except that it doesn't offer a way to feed-back
> > to gschem for things that the user *must* (in their opinion) select.
> > For example, what resistor values are available?  In what tolerances?
> > If you pick a 10uF capacitor at 10v, what's the smallest package it
> > comes in?
> 
> That's why when I do this the next screen over is a Digikey search.

When you have a corporate parts database, that's not an option.

> >   Like I've said before, the schematic is more than topology
> > - it's design.  Some attributes are intrinsic to the design, like
> > resistor/capacitor values, and should (according to some folks at
> > least) be included with the schematic.
> 
> Yes, we should support that possibility, and we do. But we should not  
> cater to the desire for a tangled flow, or a toolkit that isn't  
> easily scriptable.

Simplicity means that gschem should have access to all the attributes,
not just the few that you think deserve to be on the schematics.

> > The extra database contains (or could contain) all this information.
> 
> Millions of entries. Impractical for us to maintain.

No worse than what we already have to manually enter into schematics
now.

> > It's up to the user to specify *enough* attributes to uniquely
> > identify a specific physical part (in the pcb case at least), or in
> > combination with a BOM tool or preferences ruleset, at least be able
> > to pick something appropriate.  However, IMHO the user needs access to
> > these attribute options in gschem.
> 
> Why? gschem would just pop up some window for this anyway. Why not  
> "stand on the shoulders of giants", use the web here?

Using the web to type in "4.7k" for a resistor is just silly.
Besides, with the right back-end API, we *could* use the web as our
"database".

> > The key to heavification is that some of the inferred attributes
> > include the pin name-to-number mapping.  This lets you use really
> > light symbols without the "transistor problem" we currently have.  But
> > even then, users may want to direct this slotting from within gschem.
> 
> And we should resist the temptation to give in here.

What, you don't want the user to be able to control slotting?

> "A program should do one thing well".

But let's not limit it to just doing that one thing, or define the one
thing too narrowly.

The whole "do one thing well" saying is a trap - I wish you'd stop
using it, since one can define the "one thing" at any level, making it
a meaningless rule.  I say the one thing is "design circuits", you say
the one thing is "draw topologies".

> Every complex behavior added to gschem will make it harder to
> manipulate the design files with other tools, because those tools
> will have to satisfy the inevitable constraints the complexity puts
> on the relationships among the data objects.

But a certain amount of complexity is needed to make it a useful tool.
Otherwise, people would just use a text editor to input schematics.

> Right now, gschem is almost completely ignorant of what attributes
> mean, and I would hope this would continue to be the case.

Like refdes?

Anyway, my scheme doesn't change what gschem knows about.  It just
provides a way for attribute values to come from somewhere other than
the user's keyboard.

> As we have seen with slotting, once gschem starts to model the
> meaning of an attribute, all kinds of unanticipated problems arise.

But we *need* slotting.  It's something people complain about all the
time.  We need *more* complexity behind the scenes to *reduce*
complexity for the user.  We need to be able to control slotting and
pin swapping from both pcb and gschem, because people keep asking for
it.  *I* would like better control over pin and gate swapping.  If you
don't want such control, fine, but don't demand that others make the
same sacrifice that you make voluntarily.


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