From: Hal Fulton <hal9000@...>
Date: 2004-09-23T07:58:08+09:00
Subject: Re: Newbie: Case statement

Graham Foster wrote:
> As a newbie I'm confused about the Case construct. All the 
> documentation I've found states "case operates by comparing the 
> target with EACH of the expressions after the When keyword"
> This does NOT appear to happen, as only the first match is ever 
> actioned, so overlapping WHEN cases are skipped.

"Each" but only "until a match."

> I assume this is expected behaviour? (I'm ex-C - and was looking for 
> fall-through behaviour)

It's a strict multi-way branch; there's no fall-through from
one limb to another.

> So my underlying question is:- what's the fastest Ruby for checking 
> which of the 8 possible adjacent cells on a board (2D array) are 
> still "on the board"

I'm not sure I grasp what you mean. But you *might* try something
like this:

   ranges = {a..b=>"A",c..d=>"B",e..f=>"C",g..h=>"D",i..j=>"E"]
   # looking for 'target'
   list = ranges.reject {|x| ! x.include?(target) }
   list = list.values
   p list


Hal