From: David Alan Black <dblack@...>
Date: 2001-01-12T06:24:16+09:00
Subject: [ruby-talk:9156] Re: what about this begin?


On Fri, 12 Jan 2001, Avi Bryant wrote:

> 
> On Fri, 12 Jan 2001, [iso-8859-1] Anders Strandl�v Elkj�r wrote:
> 
> > 
> > 
> > Hiyas. I am a bit puzzled about the use of 'do', 'begin' and 'end'. Why do
> > you sometimes need the begin and other times not.
> 
> 'begin' is not needed with 'do', 'while', 'if', etc.  It is only used when
> paired with rescue/ensure to catch exceptions.  'begin' is analagous to
> 'try' in some other languages.

Also begin/end blocks can be used with certain modifiers:

  begin
    [stuff...]
  end until x > 10

There was a bunch of discussion a while ago on the interaction of these blocks
and the rescue blocks -- for instance, this:

  begin
    [stuff...]
  rescue
     [other stuff...]
  end until x > 10

will test x before running the block once.  I'm not sure what Matz's current is of
whether to retain this behavior or not.


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav