Cannot get ruby optparse to output opts

Question

I'm trying to learn how to use optparse to take in command line options however I am having a hard time getting it to function as it shows in the class documentation and any examples I can find online. Specifically when I pass the -h option nothing is coming up. I can output ARGV and its showing that it receives -h but it wont display opts.banner and or any of the opts. What am I missing here?

class TestThing

def self.parse(args)
    options = {}
        options[:time]        = 0
        options[:operation]   = :add
        options[:input_file]  = ARGV[-2]
        options[:output_file] = ARGV[-1]
            optparse = OptionParser.new do |opts|
                opts.banner = "Usage:[OPTIONS] input_file output_file"

                opts.separator = ""
                opts.separator = "Specific Options:"


                opts.on('-o', '--operation [OPERATION]', "Add or Subtract time, use 'add' or 'sub'") do |operation|
                    optopns[:operation] = operation.to_sym
                end

                opts.on('-t', '--time [TIME]', "Time to be shifted, in milliseconds") do |time|
                    options[:time] = time
                end

                opts.on_tail("-h", "--help", "Display help screen") do
                    puts opts
                    exit
                end

                opt_parser.parse!(args)
                options
            end
end
end

Answer 1

You need to hold onto the results of OptionParser.new and then call parse! on it:

op = OptionParser.new do
  # what you have now
end

op.parse!

Note that you'll need to do this outside the block you give to new, like so:

class TestThing

def self.parse(args)
    options = {}
        options[:time]        = 0
        options[:operation]   = :add
        options[:input_file]  = ARGV[-2]
        options[:output_file] = ARGV[-1]
            optparse = OptionParser.new do |opts|
                opts.banner = "Usage:[OPTIONS] input_file output_file"
                # all the rest of your app
            end
            optparse.parse!(args)
end
end

(I left your indentation in to make it clearer what I mean, but on a side note, you'll find the code easier to work with if you indent consistently).

Also, you don't need to add -h and --help - OptionParser provides those for you automatically and does exactly what you've implemented them to do.