是否可以在 Ruby 中获取关键字 arguments 的默认值？

Question

I am looking to get the default values for a function with keyword arguments. Example:

def some_method(foo: 1, bar: 2)
end

My expected output would be something like

{ foo: 1, bar: 2 }

Theparameters method defined on method only provides parameter names.

Answer 1

You can get the keys, but not the values, because they aren't actually set until the method is actually invoked. You can get the method's parameters usingMethod#parameters . For example, using your example code from above:

method(:some_method).parameters
#=> [[:key, :foo], [:key, :bar]]

However, the:foo and:bar keys aren't actually set until the method is run, so there's no way to get the "value" except possibly to introspect the method definition itself.