深入理解Ruby中的代码块block特性

puts 5 + 6
# => 11

a = 5
b = 6
puts a + b
# => 11

addition = lambda { |a, b| return a+b }
puts addition.call(5, 6)
# => 11

[1, 2, 3].each do |i|
 puts i
end

#=> 1
  2
  3

  def test;end
  test{ puts i}

def test
  yield
 end
 test{puts "hello test!"}

 def test(x)
  yield(x)
 end
 test('world!'){|x| puts "hello #{x}"}

def test(&block)
  block.call("world")
 end

 test{|msg| puts "hello #{msg}"}

 def test(&block)
  inner_test(&block)
 end

 def inner_test
  yield("haha!")
 end

 test{|msg| puts "hello #{msg}"}

empty_block = lambda { }
puts empty_block.object_id
# => 28765760
puts empty_block.class
# => Proc
puts empty_block.class.superclass
# => Object

class Calculator
 def add(a, b)
  return a+b
 end
end

puts Calculator.new.add(5, 6)
# => 11

class Calculator
 def add(a, b)
  return a+b
 end
end

addition_method = Calculator.new.method("add")
addition = addition_method.to_proc

puts addition.call(5, 6)
# => 11

Addition = lambda { |a, b| return a+b }

Subtraction = lambda { |a, b| return a-b }

Multiplication = lambda { |a, b| return a*b }

Division = lambda { |a, b| return a/b }

# 使用的时候通过call来使用
Addition.call(5, 6)
# => 11