From: Patrick Gundlach <clr10.10.randomuser@...>
Date: 2005-12-12T21:07:38+09:00
Subject: Re: increasing counter whithin loop?

Hi mental,


[...]

Your two solutions are very nice, thank you. I think I'll go for the
each_with_next.

> What's the actual problem you're trying to solve?  I'll bet there's a
> more "outside the box" solution.  

I have to print out some schedule. I create the parts by having a new
specialized class parse some xml source, do some calculation and then
output each. Let's say, one part of this schedule is a list of
members. So I have

class ListOfMembers
   def parse(src)
      # ....
   end
   def render
      # ....
   end
end

There are other items in the schedule that I need to output. I collect
all these parts in an array:

@schedule << ListOfMember.new.parse(the source)
....

and output all like

@schedule.each { |elt|  elt.render }

but in case of two 'ListOfMembers' following each other, they should be
output next to each other, so I wrap them in a 'Group of two ListOfMembers'


This is why I want to have a lookahead and a skip_next element to skip
the second 'ListOfMembers' if the first one is already one of those
and pass both to 'render two LOM'. It would have been easy in

for i in 0...schedule.size
  if schedule[i]==LOM && schedule[i+1]==LOM
    # do the two LOM thing
    i += 1
  else
    schedule[i].render
  end
end

Your ArrayStream looks very much like that, I begin to like it!

Thanks for your answer,

Patrick