[Courses] [Ruby] Lesson 2: Iterators

[Anne G]

Hi Laurel,

Thank you so much for helping with my example, so I only
have to grasp the ruby points.

I understood your example with the objecthelper. When I
tried to compile it, I got some error regarding my recursion
with lookforXs.

in `notEndofData?': stack level too deep (SystemStackError)
   from /Users/anne/Desktop/dudruby8d.rb:39:in lookforX'

I tried to use catch and throw, but it did not change the
error. How do I break from a recursion like mine?
Here is the method which calls lookforX with catch/throw

def getinfo
    # the first time we run this method, we are in a block,
    # and we store the data
        if self.notendofblock?
              @storeArr.push(writeline)
              self.increasind
              self.getinfo
    # after a while we reach the end of the block
    # and look for a new one
        else
              catch(:myrecursion) do
                   self.lookforX
              end
        end
end

And here is lookforX

def lookforX
         if self.notEndofData?
                # We found the keyword that starts a subject
                if self.trial?
                    @helper.getinfo    # go store some info
                    throw :myrecursion # break out
                # or we keep looking for the keyword
                else
                    self.lookforX
                end
         else   #end of file, we are done
                throw :myrecursion
         end
end

actually I have two recursions, lookforX method calls for
self.lookforX method, and getinfo calls for self.getinfo.
So maybe I need to break out of both recursions?

Is the use of recursions like this to be avoided?  my use of
catch and throw is not very elegant here, running across two
methods. Can it be used better? Is the alternative to use a
loop?