From: Sharon Phillips <phillipsds@...>
Date: 2007-07-22T16:51:26+09:00
Subject: Re: Syntax bug, in 1.8.5?  return not (some expr) <-- syntax error vs return (not (some expr)) <-- fine

On 22/07/2007, at 5:35 PM, Good Night Moon wrote:

> Well, it's all in the subject, to me it looks like a parsing bug:
>
> class MyRect
>   def intersects_good(other)
>     return (not ((other.x1 < self.x0 or self.x1 < other.x0) and
>                  (other.y1 < self.y0 or self.y1 < other.y0)))
>   end
>
>   def intersects_bad(other)
>     return  not ((other.x1 < self.x0 or self.x1 < other.x0) and
>                  (other.y1 < self.y0 or self.y1 < other.y0))
>   end
> end
>
>   foo> ruby -c myrect.rb
>   myrect.rb:8: syntax error, unexpected kNOT, expecting kEND
>       return  not ((other.x1 < self.x0 or self.x1 < other.x0) and
>                  ^
>
> Any comment? Is this known? Or just some hair in the Ruby grammar?

There's a difference between [not, and, or] and [!, &&, ||]
Not sure what it is, but I've found it better to use the latter.
Still, if you wrap the whole statement in another set of brackets  
(like intersects_good) it will work.

   def intersects_bad(other)
     return (not ((other.x1 < self.x0 or self.x1 < other.x0) and
                  (other.y1 < self.y0 or self.y1 < other.y0)))
   end

by the way, what's the difference between the two methods? They  
appear identical.

Cheers,
Dave