CODEWITHSUNDEEP
rubyoop
blu
blu

Reputation: 167

How can I know the type of argument a method expects?

I am trying to understand a code not written by me. How can I know the type of argument a method expects? For example, let's say I have a method:

def foo(bar)
  @bar = bar
  @baz = get_user(@bar.user)
end

How can I know which object I should send to bar?

Upvotes: 1

Views: 126

Answers (1)

Dario Barrionuevo
Dario Barrionuevo

Reputation: 3267

You can't know what kind of argument foo is waiting to receive, you only know that that object must respond to user in your example.

This principle is known as Duck Typing: With normal typing, suitability is assumed to be determined by an object's type only. In duck typing, an object's suitability is determined by the presence of certain methods and properties (with appropriate meaning), rather than the actual type of the object.

Upvotes: 4

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