TITLE: Good Sentences, Programming State Edition
AUTHOR: Eugene Wallingford
DATE: April 01, 2013  3:16 PM
DESC: 
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BODY:
I've read a couple of interesting papers recently that included
memorable sentences related to program state.

First, Stuart Sierra in
<A HREF="http://stuartsierra.com/2013/03/29/perils-of-dynamic-scope">
   On the Perils of Dynamic Scope</A>:

<BLOCKQUOTE><EM>
Global state is the zombie in the closet of every Clojure program.
</EM></BLOCKQUOTE>

This essay explains the difference between scope and extent, a
distinction that affects how easy it is to some of what happens
in a program with closures and first-order functions with free
variables.  Sierra also shows the tension between variables of
different kinds, using examples from Clojure.  An informative
read.

Next, Rob Pike in
<A HREF="http://talks.golang.org/2012/splash.article">
   Go at Google: Language Design in the Service of Software Engineering</A>,
a write-up of his SPLASH 2012 keynote address:

<BLOCKQUOTE><EM>
The motto [of the Go language] is, "Don't communicate by sharing
memory, share memory by communicating."
</EM></BLOCKQUOTE>

Imperative programmers who internalize this simple idea are on
their way to understanding and using functional programming
style effectively.  The inversion of sharing and communication
turns a lot of design and programming patterns inside out.

Pike's notes provide a comprehensive example of how a new language
can grow out of the needs of a particular set of applications,
rather than out of programming language theory.  The result can
look a little hodgepodge, but using such a language often feels
just fine.  (This reminds me of
<A HREF="http://www.cs.uni.edu/~wallingf/blog/archives/monthly/2012-12.html#e2012-12-07T11_17_07.htm">
   a different classification</A>
of languages with similar practical implications.)

~~~~

(These papers weren't published April Fool's Day, so I don't
think I've been punked.)
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