Programming Ruby 3.2 (5th Edition): missing interpolation in 'get_tax' return string (page 92)

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1

In this class get_tax method return string is missing interpolation for the @name instance variable.

class TaxCalculator
  def initialize(name, &block)
    @name, @block = name, block
  end

  def get_tax(amount)
  "#@name on #{amount} = #{ @block.call(amount) }"
  end 
end

Should be:

def get_tax(amount)
  "#{@name} on #{amount} = #{ @block.call(amount) }"
end
2

Thanks for the feedback! #@name is legal (though rare) syntax for interpolating instance variables. I think I will change it, though, if I get a chance, because the syntax is so rare. Thanks!

Noel

3

Oops, I apologise for the false alarm! I am just picking up Ruby, and haven’t seen interpolation without {} yet, so I reckoned it must have been a mistake. Thank you!

4

No problem at all, the syntax being used is quite rare in practice, and probably should be changed – good catch, thanks!

Noel

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