A recursive each method and a code block

ruby-talk
1

I have a simple search program that uses the each method with a yield to
pass back results as it finds it. However in depth first search the
method recurses at when it attempts the yield I get:

./search.rb:82:in each': no block given (LocalJumpError) from ./search.rb:77:ineach’
from ./search.rb:77:in `each’

The code is:

class DepthFirstSearch < GeneralSearch
def each(list = @partials)
# Declaring this variable outside the loop speeds things up
temp = ‘’

 list.each {|p|
   @nextitems.each {|n|
     temp = [ p.map {|x|x}, n ].flatten
     if is_valid(temp) then
       if is_result(temp) then
         @solutions += 1
         yield temp
       else
         @checked += 1
         each([temp])
       end
     end
   }
 }

end
end

I suspect the problem is, through various fiddling, that the code block
is not accessable to the subsequent recursion of the each method.

Any clues how to get this to work?

2

I have a simple search program that uses the each method with a yield to
pass back results as it finds it. However in depth first search the
method recurses at when it attempts the yield I get:

./search.rb:82:in `each': no block given (LocalJumpError)
        from ./search.rb:77:in `each'
        from ./search.rb:77:in `each'

The code is:

class DepthFirstSearch < GeneralSearch
  def each(list = @partials)

should be:

   def each(list = @partials, &block)

    # Declaring this variable outside the loop speeds things up
    temp = ''

    list.each {|p|
      @nextitems.each {|n|
        temp = [ p.map {|x|x}, n ].flatten
        if is_valid(temp) then
          if is_result(temp) then
            @solutions += 1
            yield temp
          else
            @checked += 1
            each([temp])

each is called without block.
should be:
              each([temp], &block)

          end
        end
      }
    }
  end
end

I suspect the problem is, through various fiddling, that the code block
is not accessable to the subsequent recursion of the each method.

Any clues how to get this to work?

Regards,

  Michael

···

On Mon, May 19, 2003 at 06:38:09PM +0900, Peter Hickman wrote:

3

Ow, this worked! How I managed to spend two hours fiddling with the code
and not end up trying that I don’t know.

Thanks for your help.

Typical of Ruby, its easier than you thought.