CODEWITHSUNDEEP
rubyblockanonymous-functiondsl
Sisss
Sisss

Reputation: 55

Nested blocks having arguments in Ruby

I have some serious troubles to understand blocks with arguments. I would like to use such kind of Ruby code:

FooBar.foo do |foo_arg|
  bar do |bar_arg|
    define_method :hello!, foo_arg, bar_arg do
      "Hello, #{foo_arg} and #{bar_arg}!"
    end
  end
end

include FooBar
hello!(:Alice, :Bob) # => "Hello, Alice and Bob!"

And to do so, I added thoses lines:

module FooBar
  def self.foo &foo_block
    instance_eval &foo_block
  end

  def self.bar &bar_block
    instance_eval &bar_block
  end
end

But because arguments between pipes are specials, I've got a syntax error. Thanks for any help!

Upvotes: 0

Views: 1792

Answers (1)

hjing
hjing

Reputation: 4982

Your module seems to work correctly. The issue is your usage of define_method. The parameters foo_arg, and bar_arg need to be part of the block passed to define_method.

module FooBar
  def self.foo(&foo_block)
    instance_eval &foo_block
  end

  def self.bar(&bar_block)
    instance_eval &bar_block
  end

  foo do |foo_arg|
    bar do |bar_arg|
      define_method :hello! do |foo_arg, bar_arg|
        "Hello, #{foo_arg} and #{bar_arg}!"
      end
    end
  end
end

include FooBar
hello!(:Alice, :Bob) # => "Hello, Alice and Bob!"

should do what you want.

Upvotes: 3

Related Questions