TITLE: Pascal, Forgiveness, and CS1
AUTHOR: Eugene Wallingford
DATE: June 07, 2014 10:17 AM
DESC: 
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BODY:
Last time, I thought about the
<A HREF="http://www.cs.uni.edu/~wallingf/blog/archives/monthly/2014-06.html#e2014-06-06T16_24_58.htm">
   the role of forgiveness</A>
in selecting programming languages for instruction.  I mentioned
that BASIC had worked well for me as a first programming language,
as it had worked for so many others.  Yet I would probably would
never choose it as a language for CS1, at least for more than a
few weeks of instruction.  It is missing a lot of the features
that we want CS majors to learn about early.  It's also a bit
too free.

In that post, I did say that I still consider Pascal a good
standard for first languages.  It dominated CS1 for a couple of
decades.  What made it work so well as a first instructional
language?

Pascal struck a nice balance for its time.  It was small enough
that students could master it all, and also provided constructs
for structured programming.  It had the sort of syntax that
enabled a compiler to provide students guidance about errors,
but its compilers did not seem overbearing.   It had a few
"gothchas", such as the <B><TT>;</TT></B> as a statement
separator, but not so many that students were constantly
perplexed.  (Hey to C++.)  Students were able try things out
and get programs to work without becoming demoralized by a
seemingly endless stream of complaints.

(Aside:  I have to admit that I liked Pascal's <B><TT>;</TT></B>
statement separator.  I understood it conceptually and, in
a strange way, appreciated it aesthetically.  Most others
seem to have disagreed with me...)

Python has attracted a lot of interest as a CS1 language in
recent years.  It's the first popular language in a long
while that brings to mind Pascal's feel for me.  However,
Pascal had two things that supported the teaching of CS
majors that Python does not: manifest types and pointers.
I love dynamically-typed languages with managed memory and
prefer them for my own work, but using that sort of language
in CS1 creates some new challenges when preparing students
for upper-division majors courses.

So, Pascal holds a special place for me as a CS1 language,
though it was not the language I learned there.  We used it
to teach CS1 for many years and it served me and our students
well.  I think it balances a good level of forgiveness with
a reasonable level of structure, all in a relatively small
package.
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