Question

is there any library that can inspect and display what are the arguments that a method takes?

Answer 1

I don’t know of any third-party libraries or even RubyGems that can do this reliably. It just isn’t possible to do this kind of inspection given the limited reflection facilities Ruby provides.

You will have to make do with what is available in the core library, which is basically Method#parameters:

def foo(a, b=nil, *c, d, &e); end
method(:foo).parameters
  # => [[:req, :a], [:opt, :b], [:rest, :c], [:req, :d], [:block, :e]]