usage proc for opts n stuff

slop_usage.rb

require 'slop'

opts = Slop.parse do |o|
  # ...
end

def opts.usage(msg = nil)
  puts self
  puts msg if msg
  exit 1
end

opts.usage("go home you're drunk")

usage.rb

require 'slop'

opts = Slop.parse do |o|
  # ...
end

usage = proc do |msg|
  puts opts
  puts msg if msg
  exit 1
end

usage["go home you're drunk"]