Another random idea -- "break" at toplevel

There have been times that I wanted to just skip to the bottom of
the current file.

For one example, consider this idiom (not as popular as it used
to be):

    if $0 == __FILE__
       # Possibly many lines
    end

I'd like to write this as:

    break if $0 != __FILE__

But of course, that doesn't work. And of course, exit would be
appropriate if your program itself is in the current file.

Has anyone else ever thought along these lines? I grant that the
usefulness is very limited.

A part of me thought: Well, should "break" just jump to the bottom
of the innermost enclosing context? And a part of me likes this, but
a part feels there are excellent reasons not to do it.

For example: If you're inside a method but not inside a loop, break
would act the same as return. It might confuse you if you think your
break is inside a loop but isn't -- it would return instead of giving an
error. (But if you can't tell the inside of a loop from the outside, your
code needs to be made prettier.)

Break inside a block, of course, is like a "return" from/for the block.
That, I suppose, is the only time break takes a value -- but I don't
think it would break anything (inside a method) if it *always* took a
value.

In that case, loops and class definitions could have (meaningful)
return values.

The only time I envision this "break <value>" being truly useless is
breaking from inside a required file -- we don't want to harm the
semantics of require() returning true/false, and I can't think where
else the value would go.

Unless we made "break" at toplevel of a require return true by default --
but that seems even uglier.

On a side note, the "$0 == __FILE__" expression is ugly to me. What
I really would like if something like:

    break if __REQUIRED__

or simply

    __MAIN__

But this is just me rambling. Comment or ignore as you wish.

Cheers,
Hal