ruby - 将参数传递给 Ruby 中的传入 block

Question

我想将一个 block 传递给一个函数，然后使用一些附加参数调用该 block ，如下所示:

def foo(&block)
  some_array = (1..3).to_a
  x = 7 # Simplified
  result = some_array.map &block # Need some way to pass in 'x' here
end

def a_usage_that_works
  foo do |value|
    value
  end
end

def a_usage_that_doesnt_work
  foo do |value, x|
    x # How do I pass in x?
  end
end

# rspec to demonstrate problem / required result
describe "spike" do
  it "works" do
    a_usage_that_works.should == [1,2,3]
  end
  it "doesn't work" do
    a_usage_that_doesnt_work.should == [7, 7, 7]
  end
end

如何将附加参数传递给 block ？

Answer 1

创建另一个 block 并从中调用第一个。

def foo(&block)
  some_array = (1..3).to_a
  x = 7 # Simplified
  result = some_array.map {|elem| block.call(elem, x)}
end