From: Massimiliano Mirra <list@...>
Date: 2002-09-08T00:43:58+09:00
Subject: Re: Ruby aesthetics

On Sat, Sep 07, 2002 at 01:39:55AM +0900, Yukihiro Matsumoto wrote:
> In my opiniton, the bit amount in your brain saved by eliminating
> equivalence is next to nothing.  Human brain can handle these
> equivalences very easily, unless they cause exponential combination
> explosion.

And I don't think anybody had troubles reading that last sentence
(STATEMENT unless CONDITION).

Sure, it could also be written like this:

``If these equivalences do not cause exponential combination
explosion, human brain can handle them very easily.''

But would it express the same thing?  No.  In Matz's sentence, the
statement comes first; it is read unfiltered, and it gets the most
importance; the condition appears to be exceptional and probably is
not relevant in most cases.  In the second version, the reader has to
wear conditional glasses before getting to the statement.  The how is
part of the what.

How does this translate in code?

if not File.exists?('/tmp')
  Dir.mkdir('/tmp')
end

Here I'm basically saying that I want to create /tmp.  Does a
programmer that is reading my source need to grok `if not
File.exists?('/tmp')' first?  Or am I addressing the computer, that is
not smart enough to figure out I want the directory no matter what?

I really appreciate that in Ruby I can write:

Dir.mkdir('/tmp') unless File.exists?('/tmp')

This lets me communicate my thought easily to people that think like
people rather than to people that got used to think like parsers.

(And although you might find it hard to believe, that is no invite for
anyone to flame.  That's a good skill and there's many a case I'd like
to have it.)


Massimiliano