From: Robert Klemme <shortcutter@...>
Date: 2006-09-28T03:46:19+09:00
Subject: Re: Ahh, the hazards of an interpretive language...

Pete wrote:
> This sort of thing has most probably been noted and reported by other
> people before, but as a relative newcomer to ruby I found it amusing...
> 
> At a point in the code I was writing I found I wanted an 'alternative if',
> so I glanced at the quick-reference and wrote something like this (the
> actual code being more useful, of course):
> 
>  def tt x
>   if x == :this
>    return "got this"
>   elseif x == :that
>    return "got that"
>   end
>   ## ... more actions if neither is true
>  end

Btw, the typical solution in Ruby would be to use a Hash.  Then tt will 
boil down to "def tt(x) your_hash[x] end".  The next best solution (and 
also more similar to what you did) is a case statement

def tt x
   case x
     when :this then "got this"
     when :that then "got that"
     else "foo"
   end
end

Note: semantics are not identical since this case statement uses "===" 
for evaluation of cases.  If you want identical behavior you can use

case
   when x == :this then "got this"
   ...
end

> and was totally flummoxed for half an hour or so because the second
> {':that') action was never being executed!  No error messages, ever,
> so I figured the syntax *must* be OK... (:-/)  [Ruby up to that point
> had been superb at identifying errors.]

Well, the syntax *is* ok.

> Oh well.  At least it's the sort of slip one doesn't repeat.

Certainly. :-)

Kind regards

	robert