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Message-ID: <50CB5410.5060502@zepler.net>
Date: Fri, 14 Dec 2012 16:30:08 +0000
From: Chris Smith <cjs94 AT zepler DOT net>
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To: geda-user AT delorie DOT com
Subject: Re: [geda-user] Find rat lines
References: <20121204183305 DOT 6b04c0dc AT jive DOT levalinux DOT org> <20121208112649 DOT 388a9d22 AT jive DOT levalinux DOT org> <1355011808 DOT 19390 DOT 8 DOT camel AT localhost> <alpine DOT DEB DOT 2 DOT 00 DOT 1212090407031 DOT 26605 AT igor2priv> <1355188647 DOT 12937 DOT 14 DOT camel AT localhost> <A7B4EDBD-3704-4837-9350-A16559C60A2A AT noqsi DOT com> <201212140010 DOT qBE0ABjV023762 AT envy DOT delorie DOT com> <172CCAAB-0423-43EF-8A04-5A9961F1D5B9 AT noqsi DOT com> <201212140122 DOT qBE1MoKM019255 AT envy DOT delorie DOT com>
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Reply-To: geda-user AT delorie DOT com

On 14/12/2012 01:22, DJ Delorie wrote:
>> To expand on my confusion, I cannot understand how this could be
>> difficult
> 
> An example of the difficulty: the user selects a region of items on
> the pcb and moves them to the other side, or even just moves them
> elsewhere.  The simplistic "first touch" netlist ownership method
> fails miserably with those simple commands, because a huge number of
> connections change simultaneously.
> 
> Even something as simple as adding a single trace could "short"
> multiple existing subnets, and if some of those subnets have been
> assigned to nets but some subnets are as yet unassigned (because they
> have yet to connect to something known to be in the netlist), you get
> lots of arbitrary choices to be made about how everything needs to be
> resolved.

I think much of the difficulty should disappear if the system obeys a
few simple rules: a track with a net association is never automatically
disassociated; and a track will never automatically switch association
with one net to another.  If those are followed I think even copy-paste
would not present much difficulty.

Chris
-- 
Chris Smith <cjs94 AT zepler DOT net>