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Mail Archives: geda-user/2016/01/28/04:49:40

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Subject: Re: [geda-user] The nature of gEDA layers
To: geda-user AT delorie DOT com
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From: John Griessen <john AT ecosensory DOT com>
Message-ID: <56A9E416.8080500@ecosensory.com>
Date: Thu, 28 Jan 2016 03:49:10 -0600
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On 01/28/2016 02:41 AM, Stephan Böttcher wrote:
> "Chad Parker (parker DOT charles AT gmail DOT com) [viageda-user AT delorie DOT com]"  writes:

>> >My experience has always been that hard to read spaghetti code is the
>> >result of dealing with special cases that arise from having data structures
>> >and functions that weren't designed quite right. Making things more generic
>> >reduces the number of special cases and allows for the maximum reuse of
>> >structures and functions.
>> >
>> >As I stated in my opening remark, feel free to take or leave my
>> >suggestions. Obviously I think it would be wise to heed them
> So do I.

OK.  If having generic containers for data about a pc board and an assembly of parts onto it helps coding
be easy let's do that.  Naming and documentation needs help in PCB.  The word layer gets associated with
layers of FR4  that are laminated together just by talking about board design, as in whether a layer is between ground or power 
plane layers for transmission-line purpose and/or shielding purpose...

So, if one generic container of data holds a 2D conductor on insulator pattern, and one holds
solder mask and one holds top-to-bottom-via connectivity they don't all get talked about as layers or it
is confusing.

What is a good name for these containers?  Spec group? Pattern group? Data group?
Layer is not a good name -- that should be reserved for documentation of board design concepts relation to commands and such.

If the wording data group or just group is used, you can add a word in front to concisely say most of what's needed:

For instance the futuristic buried via is likely to be specified as: attach the buried-via property to each via pad of data groups 
to connect.  All in between data groups get a default sized buried-via pad magically placed at the buried via location, but not 
more outward layer data groups.

Top to bottom via is likely to be specified as:   Add a via pad to the via data group where you want a top-to-bottom-via.

The "magically" part above will be difficult if more than one buried via not touching, but in one X,Y location is desired -- maybe 
that will
become:  place buried-via pads on each in between layer data group to connect so there is a pad at every layer data group
in between connected traces layer data groups.

Maybe pad rings in between along a vertical conductive path is not even needed by some fabbers of buried vias.


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