From: "Ara.T.Howard" <ahoward@...>
Date: 2003-12-17T02:26:59+09:00
Subject: Re: rescue block doesn't get run

On Tue, 16 Dec 2003, Hacksaw wrote:

> Date: Tue, 16 Dec 2003 22:48:11 +0900
> From: Hacksaw <hacksaw@hacksaw.org>
> Newsgroups: comp.lang.ruby
> Subject: rescue block doesn't get run
> 
> This code snippet processes the options correctly, but if I leave off a 
> required argument, it fails run my rescue block.
> 
> Why is that?
> 
> begin
>   opts = GetoptLong.new(
>                         [ "--in",      "-f",  GetoptLong::REQUIRED_ARGUMENT ],
>                         [ "--out",     "-o",  GetoptLong::REQUIRED_ARGUMENT ],
>                         [ "--version",             GetoptLong::NO_ARGUMENT ],
>                         [ "--help",    "-h", "-?", GetoptLong::NO_ARGUMENT ]
>                         )
> 
> rescue GetoptLong::MissingArgument
>   $stderr.print "Missing Argument"
>   raise
> end

/tmp > cat foo.rb
begin
  opts = GetoptLong.new(
                        [ "--in",      "-f",  GetoptLong::REQUIRED_ARGUMENT ],
                        [ "--out",     "-o",  GetoptLong::REQUIRED_ARGUMENT ],
                        [ "--version",             GetoptLong::NO_ARGUMENT ],
                        [ "--help",    "-h", "-?", GetoptLong::NO_ARGUMENT ]
                        )

rescue Exception => e
  STDERR.printf "%s\n(%s)\n%s\n", e.class, e, e.backtrace.join("\n")
end

/tmp > ruby foo.rb
NameError
(uninitialized constant GetoptLong)
foo.rb:2

/tmp > ruby -rgetoptlong foo.rb


because the error thrown is a NameError and you catch only
GetoptLong::MissingArgument.  you just need to add:

  require 'getoptlong'

to your script! ;-)

-a
-- 

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