X-Authentication-Warning:	delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient:	geda-user AT delorie DOT com
X-TCPREMOTEIP:	207.224.51.38
X-Authenticated-UID:	jpd AT noqsi DOT com
Mime-Version:	1.0 (Mac OS X Mail 7.3 \(1878.6\))
Subject:	Re: [geda-user] The nature of gEDA layers
X-Pgp-Agent:	GPGMail 2.5.2
From:	John Doty <jpd AT noqsi DOT com>
In-Reply-To:	<201601301603.u0UG3D4E023424@envy.delorie.com>
Date:	Sat, 30 Jan 2016 09:48:55 -0700
Message-Id:	<19D5ADC8-71D7-4EE6-88AB-94AD4DBF7FCE@noqsi.com>
References:	<alpine DOT DEB DOT 2 DOT 00 DOT 1601180756390 DOT 9035 AT igor2priv> <CAC4O8c-ZyNnCzCDHXkYYabSD4fG8vf+CKmhMycNJujGMPKzQDQ AT mail DOT gmail DOT com> <s6nr3h49hrq DOT fsf AT blaulicht DOT dmz DOT brux> <DDB07351-7C94-4B5C-99FA-83750CD4592A AT noqsi DOT com> <20160126233332 DOT dec2f06f5c74354a3841989c AT gmail DOT com> <s6n1t93h4ub DOT fsf AT blaulicht DOT dmz DOT brux> <20160127091746 DOT 1c7a976c2752f913921688ac AT gmail DOT com> <s6npowne74w DOT fsf AT blaulicht DOT dmz DOT brux> <20160127141334 DOT c738feb9dbeb54a7dec3dff8 AT gmail DOT com> <s6n37tjt1tv DOT fsf AT falbala DOT ieap DOT uni-kiel DOT de> <56A8F74B DOT 8080304 AT ecosensory DOT com> <CAC4O8c9UKLsh5FAAwUMEtHThKH-w3gUmCU2i9dRW9igkyRt-TQ AT mail DOT gmail DOT com> <CAJZxidDmjMtd_fKvR5qZVRa+hwDUbvfaz79oZjkBgDuE1m8RBg AT mail DOT gmail DOT com> <56A961BC DOT 3040405 AT ecosensory DOT com> <CAJZxidC=nbxAinOtpfGHHqwPXbEMrhfat7jKgA9KBp3EVVg4_Q AT mail DOT gmail DOT com> <s6nbn863xlu DOT fsf AT blaulicht DOT dmz DOT brux> <56A9E416 DOT 8080500 AT ecosensory DOT com> <s6nfuxirm0b DOT fsf AT falbala DOT ieap DOT uni-kiel DOT de> <CAC4O8c9D-F3p8sAm2UumoE+uoMZM1ufSP=mNEPeHHpn8YrcSyg AT mail DOT gmail DOT com> <20160128200126 DOT 0fe1bb26d5c28e59d56dfd0e AT gma!
	il.com> <CAC4O8c8prUS=NSm_7BCwkCPntsCRRMCMu9--eXXVBtD0C4pYOg AT mail DOT gmail DOT com> <201601282134 DOT u0SLYET7002642 AT envy DOT delorie DOT com> <82868AE2-27A4-44AE-92F2-47A2FAA12BB4 AT icloud DOT com> <201601301603 DOT u0UG3D4E023424 AT envy DOT delorie DOT com>
To:	geda-user AT delorie DOT com
X-Mailer:	Apple Mail (2.1878.6)
Reply-To:	geda-user AT delorie DOT com
Errors-To:	nobody AT delorie DOT com
X-Mailing-List:	geda-user AT delorie DOT com
X-Unsubscribes-To:	listserv AT delorie DOT com

--Apple-Mail=_49AACE09-FF3D-453E-9176-DAEE5D1360FE
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset=windows-1252


On Jan 30, 2016, at 9:03 AM, DJ Delorie <dj AT delorie DOT com> wrote:

> Despite some folks dreams to the contrary, a layout program is not a
> generic CAD program.

Whose dreams?

>  It has to have *some* understanding of what the
> layout *means* in order to be useful to the designer.  Otherwise you
> might as well use a paint program.

Nobody has ever asserted otherwise on this group. The assertion is that =
putting a layout program on a solid physical foundation make it easier =
for the designer to understand and to construct what the job needs. A =
paint program lacks that foundation. But so does pcb.

The fact that gschem is essentially a generic topology editor is a =
strength. The designer can build arbitrarily complicated structures atop =
that foundation. Again, a paint program would not suffice, but a program =
that restricted the user to a particular model of circuit design would =
not suffice either. We see the consequences of a particular model in =
drc2, which complains vehemently about all kinds of things that aren=92t =
problems, but don=92t fit its model. But, since drc2 is not part of =
gschem, its difficulties cause little harm. Hurray for separation of =
concerns!

Your sin() function in your favorite programming language does not =
understand that its argument is an angle. I suppose you=92d think this a =
problem. In fact, many applications (like Fourier analysis) depend on =
taking the sin() of variables that do not represent angles. Again, it is =
constructive to have a tool that has only a minimum of understanding and =
let the user provide that knowledge.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd AT noqsi DOT com



--Apple-Mail=_49AACE09-FF3D-453E-9176-DAEE5D1360FE
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
	filename=signature.asc
Content-Type: application/pgp-signature;
	name=signature.asc
Content-Description: Message signed with OpenPGP using GPGMail

-----BEGIN PGP SIGNATURE-----
Comment: GPGTools - https://gpgtools.org
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=Xs91
-----END PGP SIGNATURE-----

--Apple-Mail=_49AACE09-FF3D-453E-9176-DAEE5D1360FE--

- Raw text -