Question

Are only the core Ruby methods callable using object.functionName syntax? Is it possible to create methods on my own that are callable in the dot syntax fashion?

For this method:

def namechanger (name)

    nametochange = name
    puts "This is the name to change: #{nametochange}"

end

First one below works, the second does not.

namechanger("Steve")

"Steve".namechanger

I get an error on "Steve".namechanger

The error is:

rb:21:in `<main>': private method `namechanger' called for "Steve":String (NoMethodError)

Answer 1

Yes, you can add methods to the String class to achieve your desired effect; the variable “self” refers to the object which receives the method call.

class String
  def namechanger
    "This is the name to change: #{self}"
  end
end
"Steve".namechanger # => This is the name to change: Steve

This practice is known as monkey patching and should be used carefully.