From: Gary Wright <gwtmp01@...>
Date: 2011-10-20T15:01:54+09:00
Subject: Re: Call method on attribute update


On Oct 20, 2011, at 1:38 AM, Jason Lillywhite wrote:
> If @yn is updated, automatically run method "foo.calcArea". The way I
> have it now requires me to do:
> 
> foo.yn = 100.0
> foo.calcArea
> 
> There must be a way to let ruby call that method for me.


Just define the attribute writer method yourself instead of using the helpers:

class Foo
  attr_reader :yn
  def yn=(value)
    @yn = value
    calcArea
  end

  def calcArea
     puts "recomputing area"
  end
end

>> f = Foo.new      #=> #<Foo:0x1895458>
>> f.yn = 100       #=> 100
recomputing area
>> f.yn             #=> 100


Gary Wright