TITLE: Dreaming, Doing, Perl, and Language Translation
AUTHOR: Eugene Wallingford
DATE: August 24, 2010  4:30 PM
DESC: 
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BODY:
Today, I quoted Larry Wall's
<A HREF="http://dev.perl.org/perl6/talks/2000/als/larry-als.txt">
   2000 Atlanta Linux Showcase Talk</A>
in the first day of my compilers course.  In that talk,
he gives a great example of using a decompiler to port
code -- in this case, from Perl 5 to Perl 6.  While
re-reading the talk, I remembered something that
struck me as wrong when I read it the first time:

<BLOCKQUOTE><EM>
["If you can dream it, you can do it"--Walt Disney]

"If you can dream it, you can do it"--Walt Disney.  Now
this is actually false (massive laughter).  I think Walt
was confused between necessary and sufficient conditions.
If you *don't* dream it, you can't do it; that is certainly
accurate.
</EM></BLOCKQUOTE>

I don't think so.  I think this is false, too.  (Laugh now.)

It is possible to do things you don't dream of doing
first.  You certainly have to be open to doing things.
Sometimes we dream something, set out to do it, and
end up doing something else.  The history of science and
engineering are full of accidents and incidental results.

I once was tempted to say, "<EM>If you don't <B>start</B>
it, you can't do it; that is certainly accurate</EM>."
But I'm not sure that's true either, because of the
first "it".  These days, I'm more inclined to say that
if you don't start doing something, you probably won't
do anything.

Back to Day 1 of the compilers: I do love this course.
The Perl quote in my lecture notes is but one element
in a campaign to convince my students that this isn't
<B>just</B> a compilers course.  The value in the
course material and in the project itself go far beyond
the creation of an old-style source language-to-machine
language translator.  Decompilers, refactoring browsers,
cross-compilers, preprocessors, interpreters, and
translators for all sorts of domain-specific languages
-- a compilers course will help you learn about all of
these tools, both how they work and how to build them.
Besides, there aren't many better ways to consolidate
your understanding of the breadth of computer science
than to build a compiler.

The official title of my department's course is
"Translation of Programming Languages".  Back in 1994,
before the rebirth of mainstream language experimentation
and the growth of interest in scripting languages and
domain-specific languages, this seemed like a daring
step.  These days, the title seems much more fitting
than "Compiler Construction".  Perhaps my friend and
former colleague Mahmoud Pegah and I had a rare moment
of foresight.  More likely, Mahmoud had the insight,
and I was simply wise enough to follow.
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