ruby - 为什么 proc 不关心参数的数量？

Question

def method1(&proc)
  proc.call(1,2,3)
end

method1{ |x,y,z,a| puts a}

不抛出任何错误并输出nil。

为什么它不检查参数？背后的逻辑是什么？

Answer 1

Proc 不关心验证正确数量的参数，但 lambda 做...

def method1(&proc)
  proc.call(1,2,3)
end

method1 { |x,y,z,a| puts a}
method1 lambda { |x,y,z,a| puts a }

结果:

lambda.rb:1:in `method1': wrong number of arguments (given 1, expected 0) (ArgumentError)
    from lambda.rb:6:in `<main>'

来自ruby docs :

For procs created using lambda or ->() an error is generated if the wrong number of parameters are passed to a Proc with multiple parameters. For procs created using Proc.new or Kernel.proc, extra parameters are silently discarded.