Question

Ok here is what I want to do:

I pass a block to a method like: Generator.generate(...) {|x| ...}. I want to store the block because I call it in some sub routine that gets called a bunch of times from different places.

Sure I could drag along &block through all methods and calls, but I want to actually save it in a class variable and use it in the appropriate method.

Something like this:

class Generator
  class << self
    attr_accessor :my_block

    def generate(..., &block)
      my_block = &block
      ....each {important_method(x)}
    end

    def important_method(x)
      my_block.yield(x)
    end
  end
end

Is it possible to store a block and yield it later with some arguments?

Answer 1

You need to make 2 adjustments to your code:

class Generator
  class << self
    attr_accessor :my_block

    def generate(..., &block)
      self.my_block = block # Because otherwise you're just setting a method-local variable
      ....each {important_method(x)}
    end

    def important_method(x)
      my_block.call(x) # Because this is how Proc objects are called
    end
  end
end