give ruby its own version of perl's local() scoping, or "temporary-only values for existing variables."

local.markdown

I was digging around and found this little gem in a blog post on: http://banisterfiend.wordpress.com/2010/01/07/controlling-object-scope-in-ruby-1-9/

As an ex-perl hacker, I'm more partial to perl's local() rather than lisp's let()

def local
  yield
end

Thats it. Thats all there is too it. The magic is actually buried in all the rest that ruby already does.

So now you can

x = 1
local { |x|
 x = 3
 # work with x, its still 3.
}
x # is back to being 1 again. miraculously.

In ruby 1.9 you can even make it a little more suscinct.

local { |x=3|
  ...
}

go crazy, folks. go crazy.