From: Mike Ho <mike_houghton@...>
Date: 2007-10-04T21:51:40+09:00
Subject: Re: (Newbie) Override * on Array

Stefano Crocco wrote:

> 
> require 'generator'
> 
> class Array
> 
>   def *(other)
>     SyncEnumerator.new(self, other).map{|x, y| x*y}
>   end
> 
> end
> 
> Regarding errors, you I think you can check the size of the two array at 
> the
> beginning of the method and raise TypeError if they're different.
> 
> I hope this helps
> 
> Stefano

Thanks for the replies guys.

The SyncEnumerator looks elegant but when I tried it I got the following 
error

in `*': undefined method `*' for nil:NilClass (NoMethodError)

for the line

 SyncEnumerator.new(self, other).map{|x, y| x*y}


I call the method by...

a1=[2, 4, 6]
a2= [2, 2, 2]

puts a1*a2

I put some debug in like this

 def *(other)
      SyncEnumerator.new(self, other).map  do |x,y|
      puts "x #{x}  y #{y}"
      x*y
    end
  end

and the output I get is this
x 2  y 2
x 4  y 2
x 6  y 2
x   y
C:/ruby_work/test/scratch.rb:23:in `*': undefined method `*' for 
nil:NilClass (NoMethodError)
So it seems to 'run off the end'

Any thoughts ?

Thanks

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