From: Gavin Kistner <gavin@...>
Date: 2005-11-24T00:56:47+09:00
Subject: Re: How does this work?

On Nov 23, 2005, at 10:42 AM, Graham wrote:
> I cam across a construct in the FXRuby examples which I've not seen
> before..
> ..... lots of constants..(about 47 in total I believe)
>   ID_INSERT_FILE,
>   ID_EXTRACT_FILE,
>   ID_WHEELADJUST,
>   ID_LAST = enum(FXMainWindow::ID_LAST, 47)
>
> and I'm assuming this generates a unique number for each piece of  
> text,
> which is subsequently used in the rest of the code. How does it work?

Just a guess:

def enum( start, count )
   (start...start+count).to_a
end

a,b,c = enum( 101, 3 )
p a,b,c
#=> 101
#=> 102
#=> 103


Except it looks like it's using the last value to update a constant  
for future calls:

LAST_ID = 101
def enum( start, count )
   return (start...start+count).to_a
end

a,b,c,LAST_ID = enum( LAST_ID, 4 )
p a,b,c
#=> 101
#=> 102
#=> 103

d,e,f,g,LAST_ID = enum( LAST_ID, 5 )
p d,e,f,g
#=> 104
#=> 105
#=> 106
#=> 107


Note that the above (properly) generates warnings each time you  
reassign to the global value. IMO a proper 'enum' solution would keep  
track of that value internally.