Re: yields and blocks in Rails

Charles
Thu, 08 May 2008 04:34:38 -0000

I was trying to run it in some controller code. I gave up trying to do
anything fancy and just focused on getting something simple to run.
The exception name in the header is LocalJumpError, and the error
message in the box is "no block given". I placed the array extension
as the first thing in the controller file before the controller class.
I call the sample below from within a method in the controller class.

[''a'',''b'',''c'',''d''].comb(3).each
do |element|
    puts element
end

here is where it points to the errors:
app/controllers/courses_controller.rb:11:in `comb''
app/controllers/courses_controller.rb:11:in `comb''
app/controllers/courses_controller.rb:5:in `comb''
app/controllers/courses_controller.rb:10:in `comb''

Because it is the first thing in the file, the line numbers will add
up with the previous code example. They point to the yields.

thanks,
C.



On May 7, 5:09 pm, "David A. Black"
<dbl...-0o/XNnkTkwhBDgjK7y7TUQ@public.gmane.org>
wrote:
> HI --
>
>
>
> On Wed, 7 May 2008, Charles wrote:
>
> > The below code works just fine in Ruby but I get a LocalJumpError in
> > Rails stating "no block given". I thought I knew what a
block was, but
> > given the results, I am not so sure. Could someone please offer an
> > explanation as to what is going on?
>
> > Thanks,
> > C.
>
> > class Array
> >  def comb(n = size)
> >    if size < n or n < 0
> >    elsif n == 0
> >      yield([])
> >    else
> >      self[1..-1].comb(n) do |x|
> >        yield(x)
> >      end
> >      self[1..-1].comb(n - 1) do |x|
> >        yield([first] + x)
> >      end
> >    end
> >  end
> > end
>
> Can you send a case where you''re calling it and it''s
giving you that
> error?
>
> David
>
> --
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