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From: ian@sibyl.eleceng.ua.OZ (Ian Dall)
Newsgroups: comp.arch
Subject: Re: religion and computer science
Message-ID: <783@sibyl.eleceng.ua.OZ>
Date: 24 Jul 90 06:28:20 GMT
References: <20955@duke.cs.duke.edu>
Reply-To: ian@sibyl.OZ (Ian Dall)
Organization: Engineering, Uni of Adelaide, Australia
Lines: 69

In article <20955@duke.cs.duke.edu> drh@cs.duke.edu writes:
>I approached my course with what might be termed a "progressive" viewpoint.
>....
>This stretegy failed, and by the end of the course I had converted to a
>programming demogogue, mandating a very specific indentation and commenting
>style and prohibiting global variables and subprograms longer than 30 lines.
>If I had it all to do over, I would be even more rigid.

When you learn most skills you do exercises. Often coaches in physical
activities will get their charges to exagerate a certain motion in
training to improve their style. In a more closely related area, I
remember when I first learned algebra we had to write in margin the
axiom which allowed us to do each step.  Somewhere along the line a
tennis player learns that, in a match, it is better to make the shot
with his feet in the wrong position than not make the shot at all. And
somewhere along the way I learned that the axioms in the proof could
normally go unstated. I have no objection to programming *exercises*
which have a strict discipline, but they need some "match practice" as
well before they are released on the real world.

Don't get me wrong, I am all in favour of modular code etc but I have
certainly run across some people with little real experience making
dogmatic statements about *never* using goto's etc. To that extent, I
agree with the thesis that some CS people haven't acquired the
right set of priorities.

>3. Random walk indentation:  I initially allowed students to use any
>   "consistant" indentation style.  Some students reasoned that no
>   indentation is consistant, and so every line of their programs began
>   at the left margin.  (This was the popular pick from the BASIC crowd.)
>   The rest of the class must have assumed that a white noise process is
>   "consistant" since for these students the left margin looked like the
>   walk of a drunken sailor and was largely unrelated to the program's
>   structure.  Both styles resulted in the same set of problems:
>      a.  Students were unable to follow their own programming logic.
>      b.  Students spent hours looking for silly errors such as a BEGIN
>          without a matching END.
>      c.  The instructor nearly went blind trying to read the student's
>          code.
>   Only after implementing rigid and uniform indentation rules was I
>   able to bring some order to the students' programs.

I think correctly indented programs are great. The trouble is I think
it is of only marginal benefit getting the *programmer* to indent the
code.  If you make a mistake, it can be more misleading than
unindented code!  I think that these days, auto-indenting editors or
seperate programs should be available. I think that emacs c-mode has
saved me an enormous amount of time. If you leave off a ';' or have
mismatched parenthesis it becomes immediately apparant by the
indentation. If *I* had indented it, I would have indented it as I
*intended* it to work.

That is not to say that getting students to indent by hand mightn't be
a useful *exercise*, but I think getting best use out of appropriate
tools is an important skill.

>Remember when you were learning to drive, and you instructor (dad) made
>you keep both hands on the wheel at the 2 and 10 o'clock positions?  Do
>you still drive that way?  Probably not, except in heavy traffic or other
>situations which might require a quick response.

I agree except that I don't think it is quite a good analogy. Not
driving with hands at the 10 to 2 is due lazyness rather than because
it is sometimes not the best way (watch any race driver).  More
importantly, once they have learned the skills, they should be told
that they can be more flexible before they finish the course.
-- 
Ian Dall     life (n). A sexually transmitted disease which afflicts
                       some people more severely than others.