From: Peter Hickman <peter@...>
Date: 2003-05-19T18:38:09+09:00
Subject: A recursive each method and a code block

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)
     # 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?