From: Greg Fodor <gfodor@...>
Date: 2007-05-25T08:45:03+09:00
Subject: Re: Introducing the "it" keyword

> How about something like: return $1 if (v + 1) < 10 if you wanted to
> return v + 1?  If you wanted to return v you could use: return $2 if
> ((v) +1) < 10.  Improvements would be using some of the regular
> expression flags to control what $1, $2, etc. refer to.
I like this better than def it() since it seems more intentional,
but it too results in side effects into global space and prevents
GCing early.

Another problem is that you run into problems mixing the
meaning of parenthesis, since within a given expression in your
example you may not want to set aside storage space for all
parenthesized expressions, despite the fact you may need to enforce
order of operations.

For example:

puts $2 if (x + y) * (a - b) < 10

will copy the result of x + y in RAM even if your parentheses are
there to simply make the add happen first. Having it be something
new in this context like pipes separates concerns and avoids these
technical consequences.

FYI, this would be:

puts it if (x + y) * |(a - b)| < 10

We just get temp storage for a - b and preserve a single meaning
of parentheses.