From: "Shannon Fang" <xrfang / hotmail.com>
> Any comments? Since everything in ruby is object, += is a method of the
> object preceding it, why can't ++ like that?

The operator += is not a method in Ruby.   The parser treats += in a special
way.  Specifically, it treats:

    a += x

As an alias for:

    a = a + x

In that form, the + operator is a method call on the object refered to by
'a' with the object refered to by 'b' as the parameter.  The '=' is an
assignment to a local variable 'a', and is handled in a special way by the
language.

Cheers,
            Nat.