From: Robert Klemme <shortcutter@...>
Date: 2010-01-26T19:13:12+09:00
Subject: Re: Pass arguments to 'require'

2010/1/26 Xavier Noria <fxn@hashref.com>:
> Ruby takes its arguments from a global array called ARGV. That array
> is special because it is initialized by the interpreter, buy from then
> on it is a regular mutable array.
>
> In particular you can modify it:
>
>  def with_argv(*argv)
>    original_argv = ARGV.dup
>    ARGV.replace(argv)
>    yield
>    ARGV.replace(original_argv)
>  end

This is not exception safe.  You'd rather want the restoration in an
ensure block.  I would also return the result of yield rather than the
result of doing ARGV.replace.

> You would use that method this way:
>
>  with_argv(1, 2, 3) do
>    require '/opt/ruby/script1'
>  end
>
> Not that it is a good practice, you normall would invoke the scripts
> using #system or whatever, but since you say you are not a programmer
> that would fit into your current model if you don't feel confident to
> explore system.

"Require" is not a good tool in this case as it will load a script
only once and is primarily intended to be used for loading library
code.  If at all I would rather use "load".  So this would be an
alternative

def with_args(*args)
  backup = ARGV.dup
  begin
    ARGV.replace(args)
    yield
  ensure
    ARGV.replace(backup)
  end
end

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/