From: Tony Arcieri <tony.arcieri@...>
Date: 2011-01-27T13:52:25+09:00
Subject: Re: Coercion in Ruby

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On Wed, Jan 26, 2011 at 9:20 PM, David Masover <ninja@slaphack.com> wrote:

> Or at least:
>
> if other.kind_of? TimeInterval
>  ...
> elsif other.kind_of? Numeric
>  ...
>
> Remember duck typing?


Good point, but that said, it can be done even better:

First, in TimeInterval, alias_method :to_int, :value

Then when implementing +:

if other.respond_to? :to_int
  TimeInterval.new(value + other.to_int)
elsif other.respond_to? :coerce
  a, b = other.coerce(self)
  a + b
else raise TypeError, "#{other.class} can't be coerced into TimeInterval"
end

-- 
Tony Arcieri
Medioh! Kudelski

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