TITLE: == false
AUTHOR: Eugene Wallingford
DATE: December 20, 2017  3:51 PM
DESC: 
-----
BODY:
While grading one last project for the semester, I ran across
this gem:

<PRE>
    if checkInputParameters() == False:
       [...]
</PRE>

This code was not written by a beginning programmer, but a senior
who likely will graduate in May.  Sigh.

I inherited this course late in the semester, so it would be nice
if I could absolve myself of responsibility for allowing a student
to develop such a bad habit.  But this isn't the first time I've
seen this programming pattern.  I've seen it in my courses and in
other faculty's courses, in first-year courses and fourth-year
courses.  In fact, I was so certain that I blogged about the
pattern before that I spent several minutes trolling the archive.
Alas, I never found the entry.

Don't let anyone tell you that Twitter can't be helpful.  Within
minutes of tweeting
<A HREF="https://twitter.com/wallingf/status/943499910057529346">
   my dismay</A>,
two colleagues suggested new strategies for dealing with this
anti-pattern.

Sylvain Leroux
<A HREF="https://twitter.com/yes_i_know_it/status/943563349140410368">
   invoked Star Trek</A>:

<BLOCKQUOTE><EM>
 James T. Kirk "Kobayashi Maru"-style solution: Hack CPython
 to properly parse that new syntax:  <BR/><BR/>
 unless checkInputParameters(): ...
</EM></BLOCKQUOTE>

 Maybe I'll turn this into a programming exercise for the next
 student in my compiler class who wanders down the path of
 temptation.  Deep in my heart, though, I know that enterprising
 programmers will use the new type of statement to write this:

<PRE>
    unless checkInputParameters() == True:
       [...]
</PRE>

Agile Hulk
<A HREF="https://twitter.com/agile_hulk/status/943502195802234880">
   suggested a fix</A>:

<PRE>
    if (checkInputParameters() == False) == True:
</PRE>

This might actually be a productive pedagogical tack to follow:
light-hearted and spot on, highlighting the anti-pattern's flaw
by applying it to its own output.  ("Anti-pattern eats its own
dog food.")  With any luck, some students will be enlightened,
Zen-like.  Others will furrow their brow and say "What?"

... and even if we look past the boolean crime in our featured
code snippet, we really ought to take on that function name.
'Tis the season, though, and the semester is over.  I'll save
that rant for another time.
-----