scan

# File lib/rdoc/parser/perl.rb, line 51
  def scan

    @top_level.comment ||= ""
    state=:code_blank    
    line_number = 0
    line = nil

    # This started out as a really long nested case statement,
    # which also led to repetitive code.  I'd like to avoid that
    # so I'm using a "table" instead.
    
    # Firstly we need some procs to do the transition and processing
    # work.  Because these are procs they are closures, and they can
    # use variables in the local scope.
    #
    # First, the "nothing to see here" stuff.
    code_noop = lambda do 
      if line =~ /^\s+$/
        state = :code_blank
      end
    end

    pod_noop = lambda do 
      if line =~ /^\s+$/
        state = :pod_blank
      end
      @top_level.comment += filter(line)
    end

    begin_noop = lambda do 
      if line =~ /^\s+$/
        state = :begin_blank
      end
      @top_level.comment += filter(line)
    end

    # Now for the blocks that process code and comments...

    transit_to_pod = lambda do
      case line
      when /^=(?:pod|head\d+)/
        state = :pod_no_blank
        @top_level.comment += filter(line)
      when /^=over/
        state = :over_no_blank
        @top_level.comment += filter(line)
      when /^=(?:begin|for)/
        state = :begin_no_blank
      end
    end

    process_pod = lambda do
      case line
      when  /^\s*$/
        state = :pod_blank
        @top_level.comment += filter(line)
      when /^=cut/
        state = :code_no_blank
      when /^=end/
        $stderr.puts "'=end' unexpected at #{line_number} in #{@file_name}"
      else
        @top_level.comment += filter(line)
      end
    end


    process_begin = lambda do
      case line
      when  /^\s*$/
        state = :begin_blank
        @top_level.comment += filter(line)
      when /^=end/
        state = :code_no_blank
      when /^=cut/
        $stderr.puts "'=cut' unexpected at #{line_number} in #{@file_name}"
      else
        @top_level.comment += filter(line)
      end

    end


    transitions = { :code_no_blank => code_noop,
                    :code_blank => transit_to_pod,
                    :pod_no_blank => pod_noop,
                    :pod_blank => process_pod,
                    :begin_no_blank => begin_noop,
                    :begin_blank => process_begin}
    @content.each_line do |l|
      line = l
      line_number += 1
      transitions[state].call
    end # each line

    @top_level
  end