From: gotoken@... (GOTO Kentaro)
Date: 2000-10-17T03:45:37+09:00
Subject: [ruby-talk:5607] Re: passing single or multiple strings.

In message "[ruby-talk:5600] passing single or multiple strings."
    on 00/10/17, Hugh Sasse Staff Elec Eng <hgs@dmu.ac.uk> writes:

>    def something(args)
>        *bunch_of_args = args
>        bunch_of_args.each do
>            ...
>        end
>    end
>
>That's fine, and quite useful; if args are Strings and I just get one
>string then I don't get caught out by wanting to write:
>
>    case args.type
>    when Array
>       ...
>    when String
>       ...
>    end
>
>which does not work.  (You have to use if args.type == Array...elsif....
>for that.)

`type' is not needed because `Klass === obj' is identical to
`obj.is_a? Klass.'

    def something(args)
      case args
      when Array
        :Array
      when String
        :String
      end
    end

    p something([]) #=> :Array
    p something("") #=> :String

>But this is quite different:
>
>    def something(*bunch_of_args)
>        bunch_of_args.each do
>            ...
>        end
>    end
>
>because then things are not "shelled" out and if I pass in an Array I get
>a nested Array.  something(["x", "y"]) => bunch_of_args == [["x", "y"]]
>
>So what method of Array, if any, will do this "shelling" for me?

How about something(*["x", "y"]);

    def something(*bunch_of_args)
      bunch_of_args
    end

    p something(*["x", "y"]) #=> ["x", "y"]

-- gotoken