From: Philipp Meier <meier@...>
Date: 2002-09-13T19:03:09+09:00
Subject: Re: not grasping the method overloading/multi-dispatch thing


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On Fri, Sep 13, 2002 at 04:42:52PM +0900, Phil Tomson wrote:

> Yes, but what about an example like this (This is some actual code I have=
=20
> which I hesitate to show because I'm sure it's pretty smelly code, but=20
> I'm also not sure how else to do this):
>=20
> class Signal
> #....
>   def assign_at (relTime=3D0,function=3Dnil)
>     #schedule an event
>     nextValue =3D case function
>     when nil
>       Proc.new.call
>     when Proc
>       function.call
>     when Signal
>       proc{function.to_s}.call
>     else #should probably be Fixnum
>       function
>     end
>     @eventQueue[relTime] =3D nextValue
>     nextValInQueue =3D @eventQueue.shift
>     @next_value =3D nextValInQueue if nextValInQueue
>   end
>=20
>   def assign(function=3Dnil)
>     if function
>       assign_at(0,function)
>     else
>       assign_at(0,Proc.new)
>     end
>   end
>=20
>   #....
> end

What about the following?

class Signal

	@function_handlers =3D { nil =3D>  NilHandler.new,
			       Proc =3D> ProcHandler.new,
			       Signal =3D> SignalHandler.new,
			       Object =3D> DefaultHandler.new
			       }

	def assign_at(rel_Time=3D0, function=3Dnil)
		nextValue =3D @function_handlers[function.type].invoke(function)
		...
	end
end

class SignalHandler(function)
	proc{function.to_s}.call
end

class DefaultHandler(function)
	function
end

=2E..

-billy.

--=20
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