From: sto.mar@...
Date: 2012-08-04T03:21:57+09:00
Subject: Re: OptionParser error handling (InvalidArgument)

It is not clear to me what your problem is.

Slightly adapted from the post cited by you:

-----
require 'optparse'

options = {}

opts = OptionParser.new do |opts|
   # Cast 'no' argument to an Integer.
   opts.on('-n', '--no N', Integer, 'Number of...') do |no|
     options[:no] = no
   end
end

opts.parse!(ARGV)

p options
-----

results (as it should) in

$ ruby optparse.rb -n 34
{:no=>34}

$ ruby optparse.rb -n duck
optparse.rb:12:in `<main>': invalid argument: -n duck 
(OptionParser::InvalidArgument)


Am 03.08.2012 18:03, schrieb Panagiotis Atmatzidis:
> ----------------------------------------------------
> # check if options[:no] is interger
>
> if options[:no]
>          begin
>                  $no = Integer(options[:no])
>          rescue ArgumentError
>                  puts "#{$no} is not an Integer!"
>          else
>                  true
>          end
> else
>          $no = 0
> end

This is not necessary, since the option value has already been
cast to an integer, or an exception has been raised.

Btw, you should not use global variables.

> ----------------------------------------------------
> but didn't work. The error I get from cli is:
>
> f2bread.rb:483:in `<main>': invalid argument: -s duck (OptionParser::InvalidArgument)
>
> Apparently I need to somehow handle this from within OptionParser. Any ideas on how to proceed?  I found this post[1] online which explains what I want but I couldn't figure how exactly it works. So some actual codes with a sort of explanation of where *exactly* sits on the program (outside or inside "OptionParser.new" class?).
>
> The relevant OptionParser lines, where is specified that '-n' accepts Integers, are:
> ----------------------------------------------------
>   opts.on('-n', '--no N', Integer, 'Number of top entries to be displayed. By default all entries are displayed.') do |no|
>                  options[:no] = no
>          end
> ----------------------------------------------------

actually, it *did* work. "duck" is not an integer,
so an exception is raised.

> [1] http://blog.segment7.net/2008/01/05/optionparser-argument-casting


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