From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-02-01T05:38:54+09:00
Subject: Re: Local variables & blocks

On Sat, Feb 01, 2003 at 02:06:36AM +0900, Robert Klemme wrote:
> 
> Ok, I include another example to check whether I got it right:
> 
> def blocktest(*args)
>   foo = "hello"
>   p foo
> 
>   args.each do |arg|
> 
>     # local assignment
>     arg = "<#{ arg }>"
>     p arg
> 
>     # creation and assignment to 'bar' in enclosing scope
>     if defined? bar
>     then
>       # append
>       bar.concat( arg.to_s )
>     else
>       # initialization on first run
>       bar = arg.to_s
>     end
> 
>     foo = "world"
>   end
> 
>   # prints "world" if args was not empty,
>   # "hello" otherwise
>   p foo
> 
>   # prints a string containing all arguments
>   # as strings enclosed in <> if there were any
>   # otherwise raises an error...
>   p bar
> end
> 
> Since the initialization seems to be a bit verbose, I must have missed
> something. At least the test for "defined?" strikes me as unrubyish...

You can write
  (bar ||= '').concat arg.to_s
or 
  (bar ||= '') << arg
if you want fewer keystrokes :)

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