TITLE: Copying Interfaces, Copying Code
AUTHOR: Eugene Wallingford
DATE: December 05, 2016  2:42 PM
DESC: 
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BODY:
Khoi Vinh wrote a short blog entry called
<A HREF="https://www.subtraction.com/2016/08/11/the-underestimated-merits-of-copying-someone-elses-work/">
   The Underestimated Merits of Copying Someone Else's Work</A>
that reminds us how valuable copying others' work, a standard
practice in the arts, can be.  At the lowest level there is
copying at the textual level.  Sometimes, the value is mental
or mechanical:

<BLOCKQUOTE><EM>
 Hunter S. Thompson famously re-typed, word for word, F. Scott
 Fitzgerald's "The Great Gatsby" just to learn how it was done.
</EM></BLOCKQUOTE>

This made me think back to the days when people typed up code
they found in <EM>Byte</EM> magazine and other periodicals.  Of
course, typing a program gave you more than practice typing or a
sense of what it was like to type that much; it also gave you a
working program that you could use and tinker with.  I don't know
if anyone would ever copy a short story or novel by hand so that
they could morph it into something new, but we can do that
meaningfully with code.

I missed the "copy code from <EM>Byte</EM>" phase of computing.
My family never had a home computer, and by the time I got to
college and changed my major to CS, I had plenty of new programs
to write.  I pulled ideas about chess-playing programs and other
programs I wanted to write from books and magazines, but I never
typed up an entire program's source code.  (I mention one of my
first personal projects in
<A HREF="http://www.cs.uni.edu/~wallingf/blog/archives/monthly/2005-10.html#e2005-10-16T21_52_27.htm">
   an old OOPSLA workshop report</A>.)

I don't hear much these days about people copying code keystroke
for keystroke.
<A HREF="https://zedshaw.com">
   Zed Shaw</A>
has championed this idea in a series of introductory programming
books such as
<A HREF="https://learnpythonthehardway.org">
   Learn Python The Hard Way</A>.
There is probably something to be learned by copying code Hunter
Thompson-style, feeling the rhythm of syntax and format by
repetition, and soaking up semantics along the way.

Vinh has a more interesting sort of copying in mind, though:
copying the interface of a software product:

<BLOCKQUOTE><EM>
 It's odd then to realize that copying product interfaces is such
 an uncommon learning technique in design.  ... it's even easier
 to re-create designs than it is to re-create other forms of art.
 With a painting or sculpture, it's often difficult to get access
 to the historically accurate tools and materials that were used
 to create the original.  With today's product design, the tools
 are readily available; most of us already own the exact same
 software employed to create any of the most prominent product
 designs you could name.
</EM></BLOCKQUOTE>

This idea generalizes beyond interfaces to any program for which
we don't have source code.  We often talk about reverse
engineering a program, but in my experience this usually refers
to creating a program that behaves "just like" the original.
Copying an interface pixel by pixel, like copying a program or
novel character by character, requires the artist to attend to
the smallest details -- to create an exact replica, not a similar
work.

We cannot reverse engineer a program and arrive at identical
source code, of course, but we can try to replicate behavior
and interface exactly.  Doing so might help a person appreciate
the details of code more.  Such a practice might even help a
programmer learn the craft of programming in a different way.
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