From: Robert Klemme <shortcutter@...>
Date: 2009-04-15T21:05:52+09:00
Subject: Re: OptionParser and Exceptions

2009/4/15 Srijayanth Sridhar <srijayanth@gmail.com>:
> Hello,
>
> The following code:
>
> require 'optparse'
>
> optparser = OptionParser.new do |args|
>        list=[:foo,:bar,:baz]
>        begin
>                args.on("--l [OPTION]",list,"Blah") { |o| }
>        rescue
>                puts "Rescuing in the block"
>        end

This rescue does not make sense.  Because the code is invoked once
upon OptionParser.new.  Parsing errors are thrown from parse and
parse!.

> end
>
> begin
>        optparser.parse!(ARGV)
> rescue
>        puts "Rescuing in main"
> end
>
> ./foo.rb -l FOO ends up being rescued in main.
>
> Why is this? the parse! method just calls the block defined in new doesn't
> it? In which case, a begin and rescue block should work there right? Even if
> I remove the begin and rescue block in main, it doesn't get rescued at all,
> it just ends up spitting the usual ugly error etc.

You need to rescue Exception because rescue without any arguments only
rescues RuntimeErrors IIRC, it definitively does not catch every sub
class of Exception.

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
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