Path: utzoo!mnetor!uunet!husc6!bloom-beacon!athena.mit.edu!wesommer
From: wesommer@athena.mit.edu (William Sommerfeld)
Newsgroups: comp.windows.misc
Subject: Re: Why I'm suspicious of NeWS
Message-ID: <2960@bloom-beacon.MIT.EDU>
Date: 15 Feb 88 02:11:39 GMT
References: <2940@bloom-beacon.MIT.EDU> <3851@megaron.arizona.edu> <2945@bloom-beacon.MIT.EDU> <18064@topaz.rutgers.edu>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: wesommer@athena.mit.edu (William Sommerfeld)
Organization: Massachusetts Institute of Technology
Lines: 51
Keywords: [No bashing enclosed.]

I will state in advance that I have never used NeWS; I have used and
programmed X.

>The point about learning and switching languages is invalid for the
>same reason that a container whose volume is 50% occupied by water is
>both half full and half empty.  You either learn the language
>(NeWS-extended PostScript) or learn the protocol (the X protocol).

A clarification:

You don't have to ``learn the protocol'' in the sense of knowing what
the bits going over the wire look like; there are library functions
which handle all of the packing and unpacking of data for each
request.  Xlib provides a procedure-oriented interface to the
programmer.  However, you do have to understand the higher level
protocol of the way events work, but that's going to be there for any
windowing system.  If you instead use the X toolkit, most, if not all,
of the protocol details are handled by the toolkit.

My point was not that you don't need to absorb a large amount of
information to use X (you do); it is that X uses the language of your
choice for both the calls to the window system and the application,
while NeWS requires you to know both PostScript and the application
language.

C uses infix operators and prefix notation (for function calls and
control flow).

PostScript is _entirely_ postfix, including the control-flow
operators; this means that you have to scan to the _end_ of a
construct to figure out what it was.  It was designed to be easy for
machines to interpret and easy to compile to, not to be easy to
program in.  I'd rather let the compiler or interpreter manage the
stack---I've got better things to do than count stack slots.

>I have no problem going from Lisp to C to sh to Pascal to ...

Neither do I---I've written my share of shell scripts calling awk
programs which write C programs.  However, there is always a ``context
switch delay'' which increases when the languages are as radically
different as C and PostScript; whether the alleged advantanges of
PostScript make up for this is unclear.

I will say that the PostScript _imaging model_ seems to be a lot more
flexible and featureful than the X imaging model; however, I can
easily see a system which uses an X-like protocol to do PostScript
style imaging (with a transformation matrix in the graphics context,
among other things); I wouldn't be surprised if in a few years there
was a standard X extension which provided this.

				- Bill