CODEWITHSUNDEEP
ruby
OneZero
OneZero

Reputation: 11914

How to understand this code piece in ruby?

In Metaprogramming Ruby I saw this code

class String
  def to_alphanumeric
    gsub /[^\w\s]/, ''
  end
end

Here it adds a method to_alphanumeric, which substitutes punctuations with whitespace, to the standard class String. What confuses me is, since we do not specify which object gsub works on, how does Ruby know here we actually mean gsub works on the String obj itself instead of something else? Or put it in another way, does Ruby automatically rewrite it as self.gsub?

Upvotes: 0

Views: 70

Answers (1)

Mark Rushakoff
Mark Rushakoff

Reputation: 258478

The implicit receiver in Ruby is always self (and self is different in different contexts, of course).

Ruby doesn't "automatically rewrite it as self.gsub" per se, because calling a private method with an explicit self receiver will raise an exception (and gsub is a public method here anyway).

Upvotes: 7

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