TITLE: Back to Scheme in the Classroom
AUTHOR: Eugene Wallingford
DATE: September 01, 2005 10:44 PM
DESC: Are students warming to Scheme as they become more familiar with the power and convenience of scripting languages?
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BODY:
In addition to my department head duties, I am also
teaching one of my favorite courses this semester,
Programming Languages and Paradigms.  The first part
of the course introduces students to functional
programming in Scheme.

I've noticed an interesting shift in student mentality
about programming languages since I first taught this
course eight or ten years ago.  There are always
students whose interest is on learning only those
languages that they will be of immediate use to them
in their professional careers.  For them, Scheme seems
at best a distraction and at worst a waste of time.
I feel sorry for such folks, because they miss out on
a lot of beauty with their eyes so narrowly focused
on careers.  Even worse, they miss out on a chance to
learn ideas that may well show up in the languages
they will find themselves using ... such as Python
and Ruby.

But increasingly I encounter students who are much
more receptive to what Scheme can teach them.  It
seems that this shift has paralleled the rise of
scripting languages.  As students have come to use
Perl, Python, and PHP for web pages and for hacking
around with Linux, they have come to see the power
of what they call "sloppy" languages -- languages
that don't have a lot of overhead, especially as
regards static typing, that let them make crazy
mistakes, but that also empower them to say and do
a lot in a only a few lines of code.  After their
experiences in our introductory courses, where
students learn Java and Ada, students feel as if
freed when using Perl, Python, and PHP -- and, yes,
sometimes even Scheme.  Now, Scheme is hardly a
"sloppy" language in the true sense of the word,
and its strange parenthetical syntax is unforgiving.
But it gives them power to say things that were
inconvenient or darn near impossible in Java or Ada,
in very little code.  Students also come to appreciate
<A HREF="http://en.wikipedia.org/wiki/MUMPS">
   Mumps</A>,
which they learn in our Information Storage and
Retrieval course, for much the same reason.

I'm looking forward to the rest of this course, both
for its Scheme and for its programming languages
content.  What great material for a computer science
student to learn.  With any luck, they come to know
that languages and compilers aren't magic, though
sometimes they seem to do magic.  But we computer
scientists know the incantations that make them dance.

Speaking of parentheses...  Teaching Scheme again
reminds me of just how compact Scheme's list notation
can be.  In class today, we discussed lists, quotation,
and the common form of programs and data.  Quoted lists
of symbols carry all of the structural information we
need to reason about many kinds of data.  Contrast that
with the verbosity of, oh, say, XML.  (Do you remember
this
<A HREF="http://www.cs.uni.edu/~wallingf/blog/archives/monthly/2004-12.html#e2004-12-08T14_14_20.htm">
   post from the past</A>?)
Just last month
<A HREF="http://www.testing.com/cgi-bin/blog">
   Brian Marick</A>
spoke a Lisp lover's lament on an agile testing mailing
list.  Someone had said:

<BLOCKQUOTE>
Note to Brian: Explain that XML is not the be-all and
end-all of manual data formats.  Then explain it's the
easiest place to start, modulo your tool quality.
</BLOCKQUOTE>

To which Brian replied:

<BLOCKQUOTE>
I'll use XML instead of YAML as my concession to reality
and penance for not talking about Perl.  It will be hard
not to launch into my old Lisp programmer's rant about
how all the people who thought writing programs in tree
structures with parentheses was unreadable now think
writing data in tree structures with angle brackets and
keyword arguments and quotes is somehow just the cat's
pajamas.
</BLOCKQUOTE>

(<A HREF="http://www.yaml.org/">
    YAML</A>
is a lightweight, easy to read mark-up language for
use with scripting languages.  Brian might also bow
to reality and not use
<A HREF="http://www.cs.auc.dk/~normark/laml/">
    LAML</A>,
a Lispish mark-up language for the web implemented in
Scheme.)

<A HREF="http://images.google.com/images?q=rene%20magritte%20ceci%20n'est%20pas%20une%20pipe">
   <IMG SRC="http://www.cs.uni.edu/~wallingf/blog-images/art/magritte-not-a-pipe.jpg"
        ALT="Ceci n'est pas une pipe"
        WIDTH="150"
        ALIGN="right"></A>

Speaking of XML ...  Here is my favorite bit of
Angle Bracket Speak from the last month or so,
courtesy of
<A HREF="http://jtauber.com/blog/2005/08/10/old_xml_post_and_a_joke">
   James Tauber</A>:
<P ALIGN="center">
   <TT>&lt;pipe&gt;Ceci n'est pas une pipe&lt;/pipe&gt;</TT>
</P>

So that's how I'm feeling about my course right now.
Any more, when someone asks me how my class went today,
I feel like the guy answering in 
<A HREF="http://www.gapingvoid.com/Moveable_Type/archives/001422.html">
   this cartoon</A>:

<CENTER>
<IMG SRC="http://www.cs.uni.edu/~wallingf/blog-images/art/read-my-blog.jpg"
     ALT="Was it good for you? Read my blog."
     WIDTH="300">
</CENTER>
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