Re: gEDA-user: Parts DB API

[Dave N6NZ <n6nz@xxxxxxxx>]

Peter TB Brett wrote:
> On Wednesday 19 December 2007 12:48:55 DJ Delorie wrote:
>>> For the time being, however, I don't see any reason not to stick to
>>> using some sort of external helper programs for actually accessing
>>> the database, as long as we can get the UI and basic Scheme API
>>> nailed down.
>> I've argued in the past that gattrib should be responsible for
>> attributes, not gschem.
> 
> This would be nice, if not for some important points:
> 
> 1. gattrib is, sadly, a bit unstable, and not particularly new-user-friendly
>    IMHO.

Fixable.

> 
> 2. When designing schematics, quite often you need to shift backwards and
>    forwards between attribute editing/part selection and placing/moving
>    components.  You can't edit a schematic with gattrib & gschem at the same
>    time, so this involves lots of time-wasting & irritating "Save, close,
>    open" cycles.

Don't conflate the file where things are stored with the editor.

At one point I mentioned Amdahl's in house CAD system, where the 
schematic you viewed/edited was a database join of the graphics and the 
attributes.  <read-carefully>The files were not mingled. They were 
stored separately.  They were edited together.</read-carefully>

So, we need to cut loose of the idea that attributes and interconnect 
are stored in the same file.  But just because they are stored in two 
different databases, it doesn't mean they can't be edited together in a 
unified tool.

And as to it being painful to go back and forth between gschem and 
gattrib, why, by golly, you are right.  Except for the fact that it 
currently happens to be a whole lot less painful than entering all your 
attributes directly in gschem.

> 1. How do you cope with the designer deleting a component and then renumbering
>    the ones that are left?

Instances should get a unique instance number at creation time, never to 
be reused.  Refdes becomes an attached, editable attribute. If the user 
changes the refdes, the rest of the attributes don't get lost because 
they are joined to an instance number.

> 
> 2. How do you do design re-use?

By which attributes are selected from the joined file:

Today: gschem mydesign.sch -attr through-hole

Tomorrow: gschem mydesign.sch -attr surface-mount

So there is an attribute file that goes with the design.  Some 
attributes might always apply (ie: value), some are conditionally selected.

> 
> 3. It adds even further to the bundle of files you have to send to someone,
>    and which they have to artfully arrange in their filesystem, if you want to
>    share your schematics with others.

Valid point. But can't that be solved by defining a snapshot bundle, and 
  adding an "export" button? (He asks naively...)

-dave


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user