From: "ara.t.howard" <ara.t.howard@...>
Date: 2007-05-25T04:23:50+09:00
Subject: Re: Ruby, OptionParser and multiple flags


On May 24, 2007, at 10:13 AM, LDC - Jairo Eduardo Lopez wrote:

> Hello all,
>
> I'm currently writing a small script needed for my lab in which I  
> need to parse a few command line arguments in a UNIX like way.
>
> My code goes something like this:
>
> #####
> #!/usr/bin/ruby -w
>
> require 'optparse'
> require 'ostruct'
>
> opciones = OpenStruct.new
> opts = OptionParser.new do |opts|
>     opts.on("-u USER", "--uid USER", "UID del usuario.") do |usr|
>         opciones.user = usr
>     end
>
>     opts.on("-h HOST", "--host HOST", String, "Especifica el  
> servidor. Puede ser IP o DNS.") do |h|
>

> opciones.host = h
>     end
>
>     opts.on("-p PORT", "--port PORT", Integer, "Especifica el  
> puerto del servidor. Debe ser entero.") do |p|
>         opciones.port = p
>     end
> end
>
> begin
>     opts.parse!(ARGV)
> rescue Exception => e
>     puts e, opts
>     exit!
> end
>
> #####
>
> When I run the script I run into the problem that if I use various  
> flags, and forget to put in the required arguments, some flags are  
> taken as arguments. I've read that if I use the coding I've used  
> all three flags, the argument should be obligatory.
>
> To better explain, I'll give some examples:
>
> -----
> ./script.rb -h
> missing argument: -h
> -----
> Works fine.
>
> -----
> ./script.rb -p
> missing argument: -p
> -----
> Works fine.
>
> -----
> ./script.rb -h -p -----
> The script accepts -p as the argument for -h, which shouldn't  
> happen as -p is actually a flag.
>
> I'm not sure what the problem is so I need help.

you've told the option parser that -h accepts an argument and you've  
given it one.  there is no restriction that arguments must not start  
with a '-' so, in this case, your code is doing it exactly what you  
told it to do ;-)


-a
--
we can deny everything, except that we have the possibility of being  
better. simply reflect on that.
h.h. the 14th dalai lama