From: James Coglan <jcoglan@...>
Date: 2009-08-27T18:17:43+09:00
Subject: Re: A bizarre problem with data= methods

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2009/8/27 David Espada <davinciSINSPAM@escomposlinuxagujero-negro.org>

> Hi all.
>
> I have found an error that does not understand. Look this simple code:
>
> ---------------------------------
> class Foo
>  def value=(data)
>    puts "Look #{data}"
>  end
> end
>
> f = Foo.new.value = "at me" # => Look at me
> ---------------------------------
>
> Great! A little assigner that works perfectly. But now I make a
> constructor that use the assigner directly:
>
> ---------------------------------
> class Foo
>  def initialize(data)
>    value = data
>  end
>
>  def value=(data)
>    puts "Look #{data}"
>  end
> end
>
> f = Foo.new("at me") # => Nothing!!!!!!!!!
> ---------------------------------
>
> Why? The constructor doesn't use value= method. What is happening? Is
> that normal?



You need an explicit self, ie. `self.value = data`. Without the `self`, Ruby
interprets that line as a local variable assignment, not a method call.

--
James Coglan
http://jcoglan.com

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