From: Ryan Davis <ryand@...>
Date: 2009-12-23T19:39:09+09:00
Subject: Re: Strange behavior of unary +@ for Fixnum?


On Dec 23, 2009, at 01:37 , Alexandre Mutel wrote:

> Marc Heiler wrote:
>> I think it is a quite short topic actually.
>> 
>> Which operators are commonly overloaded in ruby?
> 
> I mean, when you need to use intensively operators, there are lots of 
> (small) issues, difference between 1.8.x and 1.9.x, difference with 
> JRuby with --1.9 switch... Actually, I'm using operators overloading for 
> a DSL to accept new If/Else/Elsif expressions, and have to deal with 
> those issues.

> For example the unary +@ operator on symbols is not really working in 
> 1.8.x.

How is it not working on symbols?

class Symbol
 def +@
   puts "YES #{self}"
 end

 def -@
   puts "NO #{self}"
 end
end

-:x          # => NO x
+:x          # => :x
+(:x)        # => YES x
-(:x)        # => NO x
+(:x)        # => YES x
:x.send(:-@) # => NO x
:x.send(:+@) # => YES x

> As well as the ! operator that was finally introduced in 1.9.x. 

Have you filed any bugs (or even sent email) against ruby-core for the ! operator?

> For the Fixnum, i didn't find any documentation (until here) that states 
> that +@ operator for numeric are in fact consumed by the parser as 
> literals...

Did you actually look at a grammar for ruby? There has been one online for just about forever (granted it is from 1.4, but I don't think it has changed all that much in this arena). You can also look at ParseTree's output, or ruby_parser's, or, or, or...