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From: Pietro Gagliardi <pietro10@mac.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
In-Reply-To: <cf4af653e1e33047d61c983882d11401@quintile.net>
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Date: Mon, 19 May 2008 16:45:36 -0400
References: <cf4af653e1e33047d61c983882d11401@quintile.net>
Subject: Re: [9fans] dag pic preprocessor
Topicbox-Message-UUID: ab3ec312-ead3-11e9-9d60-3106f5b1d025

On May 19, 2008, at 10:08 AM, Steve Simon wrote:

> Hi,
>
> I want to draw some DAGs. Dot (part of graphviz) seems to be the
> way to do it these days, however looking at the sources I wondered
> if there was a smaller simpler way to do this.
>
> I found a reference to dag, a pic preprocessor which seems to
> be a forunner of dot. Is the source available anywhere?
>
> http://citeseer.ist.psu.edu/gansner89dag.html
>
> -Steve
>

I asked about that. Got one response so far, but no code yet.

north@research.att.com

I think you can make a simple dot preprocessor using awk and pipes
(GraphViz is in /n/sources/extra):

	BEGIN { in_it = 0 }

	/^\.begin (dot|neato)/ { in_it = 1; program = $2 " -Tpic"; next }
	/^\.end/ { close(program); in_it = 0; next }

	!in_it { print; next }

	{ print | program }

	END { if (in_it) print "unclosed graph" | "cat 1>&2" }