# File lib/parslet/atoms/lookahead.rb, line 11
  def initialize(bound_parslet, positive=true)
    super()
    
    # Model positive and negative lookahead by testing this flag.
    @positive = positive
    @bound_parslet = bound_parslet
    
    @error_msgs = {
      :positive => ["Input should start with ", bound_parslet], 
      :negative => ["Input should not start with ", bound_parslet]
    }
  end