From: Panagiotis Atmatzidis <ml@...>
Date: 2012-08-04T01:03:48+09:00
Subject: OptionParser error handling (InvalidArgument)

Hello,

I'd like to make an OptParser error look a bit more explanatory. I tried to deal with it outside OpiontParser like this:

----------------------------------------------------
# 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
----------------------------------------------------
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
----------------------------------------------------

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

Best Regards,

Panagiotis Atmatzidis
-----------------------------
Pharmacy Student at VFU

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