TITLE: Part of the Fun of Programming
AUTHOR: Eugene Wallingford
DATE: March 22, 2017  4:50 PM
DESC: 
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BODY:
 As I got ready for class yesterday morning, I decided to refactor
 a piece of code.  No big deal, right?  It turned out to be a
 bigger deal than I expected.  That's part of the fun of
 programming.

 The function in question is a lexical addresser for a little
 language we use as a specimen in my Programming Languages course.
 My students had been working on a design, and it was time for us
 to build a solution as a group.  Looking at my code from the
 previous semester, I thought that changing the order of two cases
 would make for a better story in class.  The cases are independent,
 so I swapped them and ran my tests.

 The change broke my code.  It turns out that the old "else" clause
 had been serving as a convenient catch-all and was only working
 correctly due to an error in another function.  Swapping the cases
 exposed the error.

 Ordinarily, this wouldn't be a big deal, either.  I would simply
 fix the code and give my students a correct solution.  Unfortunately,
 I had less than an hour before class, so I now found myself in a
 scramble to find the bug, fix it, and make the changes to my lecture
 notes that had motivated the refactor in the first place.  Making
 changes like this under time pressure is rarely a good idea...  I
 was tempted to revert to the previous version, teach class, and make
 the change after class.  But I am a programmer, dogged and often
 foolhardy, so I pressed on.
 
 With a few minutes to spare, I closed the editor on my lecture notes
 and synced the files to my teaching machine.  I was tired and still
 had a little nervous energy coursing through me, but I felt great.
 That's part of the fun of programming.

 I will say this:  Boy, was I glad to have my test suite!  It was
 incomplete, of course, because I found an error in my program.
 But the tests I did have helped me to know that my bug fix had
 not broken something else unexpectedly.  The error I found led to
 several new tests that make the test suite stronger.

 This experience was fresh in my mind this morning when I read 
<A HREF="http://news.harvard.edu/gazette/story/2014/05/physics-was-paradise/">
   "Physics Was Paradise"</A>,
 an interview with Melissa Franklin, a distinguished experimental
 particle physicist at Harvard.  At one point, Franklin mentioned
 taking her first physics course in high school.  The interviewer
 asked if physics immediately stood out as something she would
 dedicate her life to.  Franklin responded:

<BLOCKQUOTE><EM>
 Physics is interesting, but it didn't all of a sudden grab me
 because introductory physics doesn't automatically grab
 people.  At that time, I was still interested in being a
 writer or a philosopher.
</EM></BLOCKQUOTE>

 I took my first programming class in high school and, while I
 liked it very much, it did not cause me to change my longstanding
 intention to major in architecture.  After starting in the
 architecture program, I began to sense that, while I liked
 architecture and had much to learn from it, computer science was
 where my future lay.  Maybe somewhere deep in my mind was memory
 of an experience like the one I had yesterday, battling a piece
 of code and coming out with a sense of accomplishment and a
 desire to do battle again.  I didn't feel the same way when
 working on problems in my architecture courses.

 Intro CS, like intro physics, doesn't always snatch people away
 from their goals and dreams.  But if you enjoy the fun of
 programming, eventually it sneaks up on you.
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