From: Anders Borch <spam@...>
Date: 2003-07-17T18:54:44+09:00
Subject: Re: Keyword "with"

Michael Campbell wrote:
>>The fundamental reason, I think,
>>is that a Fixnum object (upon which such an operator would operate)
>>should never be mutable.
> 
> 
> Yes.
> 
> 
>>The x+=1 operator emphasizes that a new Fixnum
>>object is being assigned to the applicable variable.
> 
> 
> No.  (To me, anyway).
> 
> I can't say I associate "new object being created" with "+=".  Now I know,
> deep down, that it's syntactic equivalence to "= .. + ..", and THAT
> emphasizes "new object", but on a more gutteral level, "+=" means "new
> object creation" no more than "++" would.
> 
> Maybe that's me though.
> 
> 

I couldn't help myself any longer, I *had* to implement the ++ operator

Sadly, we have to load the file with ++ calls explicitly, since a file 
is parsed before anything is executed, so the appearance of ++ would 
generate parse errors before we could catch them and replace them with 
'+=1'. So, I wrote a new load method:

def loadpp(l)
   s = ''
   prevb = nil
   f = File.new(l,'r')
   f.each_byte do |b|
     if (b == 43 && b == prevb) # 43 is ascii '+'
       s += '+= 1 '
       b = nil # throw away the '++'
     else
       s += prevb.chr unless prevb.nil?
     end
     prevb = b
   end
   s += prevb.chr unless prevb.nil?
   eval(s)
end

Now, any file loaded with loadpp may contain the ++ operator, and it 
will be replaced with '+= 1'. Have fun with it if you like :)

/Anders