From: RichardOnRails <RichardDummyMailbox58407@...>
Date: 2008-08-28T10:10:24+09:00
Subject: Re: Access to method in superclass

On Aug 26, 11:19 am, David Colque <d_col...@yahoo.es> wrote:
> RichardOnRails wrote:
> > On Aug 25, 2:35 pm, David Colque <d_col...@yahoo.es> wrote:
> >> LIKE ACCEDING TO THE METHOD " setSpeed" OF THE SUPERCLASS "Airplane".
> >> Thak you
>
> >> Attachments:http://www.ruby-forum.com/attachment/2606/prueba1.rb
>
> >> --
> >> Posted viahttp://www.ruby-forum.com/.
>
> > Hi David,
>
> > Your access to Airplane::setSpeed is working.
>
> > On line 55, you create an Airplane::Jet instance with @speed=0
> > On line 56, you invoke that setSpeed on the instance with argument 422
> >   so the method on line 38 is called with 422
> >   which in turn invokes Airplane::setSpeed with the argument
> > 422*Multiplier, of 844,
> >   which is then set in @speed of the Airplane::Jet instance
> > On line 57, you print out the 844
>
> > Then on line 57, you invoke
>
> > Line 56 set the Jet's speed to 0
> > Line 57 with argument 422 set the Jet's speed to 422*Multiplier, or
> > 844 and printed it
>
> > Line 60 invoked accelerate, which in turn invoked
> > Line 45 setSpeed(getSpeed()*2)
> >   getSpeed returned your 844, which then got doubled to 1688
> >   which was used as the argument to setSpped, which applied the
> > Multiplier
> >   so the speed was set to 3376
> > Line 61 used getSpeed to retrieve the 3376, which then got printed.
>
> > All this is confirmed by lines 2 and 2 of your output.
>
> > HTH,
> > Richard
>
> class Jet < Airplane
>   MULTIPLIER = 2
>   def initialize
>     super
>   end
>   def setSpeed(speed)
>     super(speed*MULTIPLIER)
>   end
>   def accelerate
>     # TROUBLE!!!!!!!!
>     # LIKE ACCEDING TO THE METHOD " setSpeed"
>     # OF THE SUPERCLASS "Airplane"
>     Airplane::setSpeed(getSpeed()*2)
>   end
>
> end
>
> At the time of making it run it leaves the error>ruby prueba1.rb
>
> prueba1.rb:28:in `accelerate': undefined method `setSpeed' for
> Airplane:Class (NoMethodError)
>   from prueba1.rb:43:in `principal'
>   from prueba1.rb:57
> 212
> 844>Exit code: 1
>
> --
> Posted viahttp://www.ruby-forum.com/.

Hi David,

I can’t see what’s wrong on your program/machine.

I ran the code you posted unchanged and got the following output:
212
844
3376
54016
216064
864256
1696


The first question I’d ask is, what version of Ruby/OS are you
running ... though I doubt that will be too helpful?  I’m running:
ruby 1.8.6 (2007-09-24 patchlevel 111) [i386-mswin32]
WinXP-Pro/SP2

The second question is, are you up to cleaning up code and debugging
it?  At http://www.pastie.org/261401,  I posted a version of your
program that is closer to what I understand to be “The Ruby Way”.  I
don’t understand your purpose,  so I can’t do anymore.  I hope this
version runs on your machine as it does on mine.  I also hope it leads
to a clearer understanding of your program flow.

The version I posted doesn’t produce the same numbers that your
original did,  but I don’t want to spend anymore time on it.  As I
said,  my goal is to help you get closer to “The Ruby Way.”

Best wishes,
Richard