Re: gEDA: Proposal: Make symbol files nestable

[Magnus Danielson <cfmd-at-NOSPAMswipnet_dot_se>]

From: "J.D. Bakker" <bakker@thorgal.et.tudelft.nl>
Subject: gEDA: Proposal: Make symbol files nestable (was: Type numbers for transistors)
Date: Mon, 25 Feb 2002 14:37:07 +0100

> Hi,

Hi,

> I've followed the discussions on gschem symbols for a while, and it 
> seems to me that there is a conceptually simple solution to all the 
> 'one symbol, multiple packages' issue: nestable symbols.
> 
> Instead of the current situation, where we have a 7400.sym, a 74LS00 
> .sym, a 74HC00.sym etc, all of which effectively have 95% overlap, 
> wouldn't we be better off with:
> 
> NAND2.sym:
> <drawing and pin definitions for a NAND2>
> 
> 7400_generic.sym:
> C 0 0 1 0 0 NAND2.sym <for lack of a better #include directive>
> numslots=4
> slot1=1,2,3
> slot2=4,5,6
> slot3=9,10,8
> slot4=12,13,11
> <power and ground nets, if desired>
> 
> SN74AC00PWR:
> C 0 0 1 0 0 NAND2.sym
> device=SN74AC00PWR
> footprint=TSSOP-14
> manufacturer=Texas_Instruments
> url="http://www-s.ti.com/sc/psheets/...
> 
> The same goes for transistors, diodes, LEDs and the like. This would 
> IMO solve a lot of problems by abstracting symbols from devices.

This is effectively doing what I have been proposing for a long time,
namely separate the symbols and components. In such a system the
symbol is only the graphical representation where as the component
declarations describe the details for a certain component.

> I know that in the Open Source/Free Software tradition I should have 
> attached a patch at this point. Sorry, no time yet. It's a poor 
> excuse, but it's the best one I have.
> 
> Thoughts ? Opinions ? Flames ?

Indeed a quite concrete proposal.

Cheers,
Magnus