How do Ruby closures work?

ruby-closure-confusion.rb

greeting = "Hello"

def greeter
  puts greeting
end

greeter

# undefined local variable or method `greeting' for main:Object (NameError)

I wish I knew all the rules for ruby closures. I tend to use instance variables for this kind of thing. To start to edge towards some insight, I did this: https://gist.github.com/3375580

I think this is what I know about this:

1. a method creates a new binding, so it doesn't have access to the closure around it
2. a proc (lambda, block, all that stuff) does inherit the closure around it
3. methods don't pass their closures between them

Basically, Ruby closures are really different than JavaScript, which would let you share/inherit closures a bit differently. I did find a description about this kind of thing in The Ruby Way, section 1.5.4, if you happen to have access to that.

Methods are not lexical closures, so I'm not sure what you're asking here?

If you want a lexical closure you need to use define_method instead.