Is it possible to refer to the parameter passed to the method in the passed block in ruby?

Question

I hope I’m not repeating anyone here, but I searched Google here, and didn’t invent anything. This question is really more important for the "decomposition" of my code.

What I'm specifically trying to do is the following:

Dir.new('some_directory').each do |file| # is there a way to refer to the string 'some_directory' via a method or variable? end 

Thanks!

Answer 1

Not in general; it completely depends on the method itself, which arguments the block was called to, and by the time each was called (which calls your block), the fact that the string 'some_directory' was passed to Dir.new has long been forgotten, i.e. they are completely different.

You can do something like this:

 Dir.new(my_dir = 'some_directory').each do |file| puts "#{my_dir} contains #{file}" end 

Answer 2

The reason it will not work is because new and each are two different methods, so they do not have access to each other's parameters. To “develop” your code, you might consider creating a new method that would contain two method calls and pass it a repeating parameter:

 def do_something(dir) Dir.new(dir).each do |file| # use dir in some way end end 

The fact that creating a new method has such low overhead means that it is quite reasonable to create one for such a small piece of code as this, and this is one of many reasons why Ruby is so nice to use the language with.

Answer 3

Just decompose it into a variable. Ruby blocks are private, so they will have access -

 dir = 'some_directory' Dir.new(dir).each do |file| # use dir here as expected. end