当块已经有自己的作用域时，设置 Ruby 块局部变量的目的是什么？

Learning about Ruby blocks here http://rubylearning.com/satishtalim/ruby_blocks.html. What is the point of having block local variable in this example:

When you can just do the below instead? The x in the block is already going to have its own scope, which is different than the x that is outside the block.

块作用域nest在它们的词法封闭范围内：

foo = :outerfoo
bar = :outerbar

1.times do |;bar|
  foo = :innerfoo
  bar = :innerbar
  baz = :innerbaz
end

foo #=> :innerfoo
bar #=> :outerbar
baz # NameError

您需要一种方法来告诉 Ruby：“我不需要外部作用域中的这个变量，我想要一个新的变量。”这就是块局部变量的作用。