From: Gavin Sinclair <gsinclair@...>
Date: 2004-02-01T21:57:27+09:00
Subject: Re: Save the flip/flop op!

On Sunday, February 1, 2004, 11:29:50 PM, Robert wrote:

>> Comments, Phil? Nathaniel? Others?

> I wouldn't put it into File or IO since this is too specialized
> functionality.  It deserves a class of it's own:

> class FlipFlop
>   def initialize(on, off)
>     @on, @off = on, off
>     @state = false
>   end
>
>   def ===(o)
>     if @state
>       @state = false if @off === o
>     else
>       @state = true if @on === o
>     end
>
>     @state
>   end
> end


Nice implementation.  The usage is still more verbose than the FF
operator, though.  Perhaps some method to process an enumerable
object?

# Untested
class FlipFlop
  def process(enum)
    enum.each do |o|
      yield(o) if self === o
    end
  end
end


File.open(path) do |io|
  FlipFlop.new(/BEGIN/, /END/).process(io) do |line|
    puts line
  end
end

Is that any good?

Gavin