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Message-ID: <50084839.9080804@sbcglobal.net>
Date: Thu, 19 Jul 2012 10:47:37 -0700
From: "Girvin R. Herr" <girvin DOT herr AT sbcglobal DOT net>
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To: gEDA User Mailing List <geda-user AT delorie DOT com>
Subject: [geda-user] Symbol attributes
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Greetings,
According to the gEDA/gaf Symbol Creation Document:

    * device=DEVICENAME should be placed somewhere in the symbol and
      made invisible.  ... This attribute should not be used as a label.
      Use a separate text object for the label.  ... "

Although many of the library symbols violate this "requirement" and use 
"device" as the value-visible device name, i.e. "7400", in the 
schematic.  In all symbols that I have used, "device" is editable after 
instantiation into a schematic, but according to the above, I should not 
be using "device" in this manner.  So, for my symbols, I have created an 
attribute I call "partname", which is visible when the symbol is 
instantiated into a schematic.  However, sometimes this attribute is 
tagged as an "inherited attribute" and as such is not editable in the 
instantiated symbol.  This attribute tagging as inherited or not seems 
to change arbitrarily and I do not know how to control it.  For 
instance, a symbol of mine which uses the "partname" attribute as 
visible and "device" as invisible per the document, allows editing the 
symbol's "partname" attribute after instantiation.  When I edited the 
symbol and made "partname" invisible and "device" visible, that 
instantiated symbol lists "partname" as inherited and no longer 
editable.  The visibility setting does not seem to be the determining 
factor, since other invisible attributes are editable after 
instantiation, such as "footprint" and "symversion".
My question is, what determines an attribute as basic 
(schematic-editable) or "Inherited" (not schematic-editable)?
Or, more to the point: How do I set the editability of an attribute in 
an instantiated symbol?

I am at a point where I need to commit to either violating the 
"requirements" and use "device" as the visible and editable part name 
attribute or using my "partname" attribute for the part name.  But i 
need to understand this control behavior before I can commit.
Thanks in advance.
Girvin Herr