Path: utzoo!yunexus!ists!jarvis.csri.toronto.edu!mailrus!uunet!snorkelwacker!bloom-beacon!eru!luth!sunic!tut!tukki!sakkinen
From: sakkinen@tukki.jyu.fi (Markku Sakkinen)
Newsgroups: comp.lang.visual,comp.lang.misc
Subject: Re: metaphor and programming
Message-ID: <2049@tukki.jyu.fi>
Date: 17 Nov 89 14:19:04 GMT
Article-I.D.: tukki.2049
References: <13770@orstcs.CS.ORST.EDU> <7000@ficc.uu.net> <1989Nov17.040858.22886@rpi.edu>
Reply-To: sakkinen@jytko.jyu.fi (Markku Sakkinen)
          SAKKINEN@FINJYU.bitnet (alternative)
Organization: University of Jyvaskyla, Finland
Lines: 31

In article <1989Nov17.040858.22886@rpi.edu> mcintyre@turing.cs.rpi.edu (David McIntyre) writes:
-In article <7000@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
->I think visual languages would be most closely related to the dataflow
->metaphor. That is the most dimensionally ordered one. Think of building
->UNIX shell programs by fitting together pipes to little tanks called
->"awk" and "sed"...
->
-
-I am not so sure about this.  Let's stay with the example of a Unix pipe
-"program".  This is always a one-dimensional flow of data.  I am not
-sure that a visual representation of this would add anything, although
-it might make building pipes more fun.
-
-[...]

The one-dimensionality is only a restriction of the conventional
UNIX command interpreters ("shells"), not of pipes as such.
See the article of McDonald and Dix
in Software - Practice and Experience (October 1988).
It describes a "graph shell" (gsh) that allows arbitrary networks
of pipes to be constructed.
However, most standard UNIX programmes have been designed with
one input and at most two outputs, so the potential advantages
of a graph shell cannot be fully exploited with them.

Markku Sakkinen
Department of Computer Science
University of Jyvaskyla (a's with umlauts)
Seminaarinkatu 15
SF-40100 Jyvaskyla (umlauts again)
Finland