From: Gavin Sinclair <gsinclair@...>
Date: 2003-12-11T11:12:30+09:00
Subject: Re: Ideas for replacing $0==__FILE__

>
> I've recently found that it is sometimes useful to combine a "main" Ruby
> program with required modules into a single file.

I'm not entirely sure what you mean here.  Can we have an example?

> [...]

> Do people really consider this idiom to be *that* useful? Most of the
> times I've seen it used, it wraps either examples (better done in
> separate files, you can have more than one and more complex), or tests
> (*much* better done with Test::Unit).

I commonly wrap Test::Unit tests in 'if $0 == __FILE__'.  It's easier to
edit and execute the tests when they're in the same file.  It's less files
in the distribution and no 'how do I include the library in the library
path from the unit test file?' hassles.

Concerning the idiom itself, I initially thought it ugly and pondered the
benefit of a "main" function (i.e. at the top level, def main(*args)). 
Having come to appreciate the importance of runtime in Ruby, though, I now
think it is appropriate for programmers to be aware of, and take control
of, what happens when their files are loaded, and in what context. 
Therefore I find the idiom aesthetically unappealing but conceptually
acceptable.

Given this, I have little taste for the proposed __MAIN__, __TEST__, etc.
directives.

Gavin