From: Jeremy Hinegardner <jeremy@...>
Date: 2007-05-28T12:15:37+09:00
Subject: Re: please help me with OptionParser

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On Mon, May 28, 2007 at 03:17:32AM +0900, Christopher J. Bottaro wrote:
> Here's the pastebin of this post if you prefer looking at formatted
> source:
> http://pastebin.ca/514353
> 
> Ok, I'm having a multitude of problems with OptionParser.  First, I
> can't get it to work following the online documentation.

Which online documentation are you using?

http://www.ruby-doc.org/stdlib/libdoc/optparse/rdoc/classes/OptionParser.html

That's the documentation that I use.

> Second, I got it to work by adding :REQUIRED to the on() method call,
> but that doesn't work as expected:  the argument isn't really
> "required"; OptionParser does not bomb if the argument is omitted.

That's not actually how you do it.  The style to code up a required
argument is:

    opts.on("-c", "--client ID", "client id to migrate for")

Putting something after the option tells option parser that you
require an argument on that option.  In this cases putting ID after
--client tells the parser that this option has a required argument.
use [ID] to designate option parameters.  
    
To force ID to be an integer, you can change the option to be:

    opts.on("-c", "--client ID", Integer, "client id to migrate for")
    ...

This will make sure that ID is an Integer before passing to the block.
If it isn't it will throw and exception.

> Third, I cannot get a switch to accept multiple arguments.
> --my_arg 1 2 3
> I want an array [1, 2, 3].

Array style arguments are done as comma separated items that are passed
to the block as an Array.  So ch

    opts.on("-c", "--client ID,ID", Array, "client id(s) to migrate for")
    ...

In your case, it seems you want to make sure that the option parameters
to ID is an Array of Integers.  Which means you'll have to tweak it a
bit for yourself.  I've written up one solution in the attached .rb
file.

> Thanks for the help, the rest of the message contains my pastebin
> post:
> 

Play with the attached test cases and make it do what you want.  I made
tests to describe what you wanted, and the Application class that is
tested meets those test.

enjoy,

-jeremy

-- 
========================================================================
 Jeremy Hinegardner                              jeremy@hinegardner.org 


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#!/usr/bin/env ruby
require 'optparse'
require 'ostruct'
require 'test/unit'

class OptionParserTestApplication

    attr_accessor :options

    def initialize
        @options = default_options
        @parser  = option_parser

    end
    def run(argv = [])
        begin
            @parser.parse!(argv)
        rescue OptionParser::ParseError => pe
            puts pe
            puts @parser
            exit 1
        end
    end

    def default_options
        op = OpenStruct.new
        op.client_ids = []
        op.save = false
        return op
    end

    def option_parser
        OptionParser.new do |opts|
            opts.on("-c", "--client ID,LIST", Array,"client id to migrate for") do |client_id_list|
                client_id_list.each do |cid|
                    begin
                        @options.client_ids << Integer(cid)
                    rescue ArgumentError => e
                        raise OptionParser::ParseError, "#{cid} is not an integer"
                    end
                end
            end

            opts.on_tail("-h", "--help", "Show this message") do
                puts opts
                exit
            end
        end
    end
end

class TestOptions < Test::Unit::TestCase

    def setup
        @app = OptionParserTestApplication.new
    end

    def test_client_id_required
        argv = %w(--client)
        assert_raise(SystemExit) { @app.run(argv) }
    end

    def test_client_ids_are_integer
        argv = %w(--client 123)
        @app.run(argv)
        assert_equal(123,@app.options.client_ids.first)
    end

    def test_client_ids_as_array
        argv = %w(--client 123,456)
        @app.run(argv)
        assert_equal(2,@app.options.client_ids.size)
        assert(@app.options.client_ids.include?(123))
        assert(@app.options.client_ids.include?(456))
    end

    def test_client_ids_as_array_of_integers
        argv = %w(--client 123,not-a-number)
        assert_raise(SystemExit) { @app.run(argv) }
    end
end

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