From: "Berger, Daniel" <Daniel.Berger@...>
Date: 2007-11-13T07:34:48+09:00
Subject: Re: Time#== bug?

 

> -----Original Message-----
> From: murphy [mailto:murphy@rubychan.de] 
> Sent: Monday, November 12, 2007 12:55 PM
> To: ruby-core@ruby-lang.org
> Subject: Re: Time#== bug?
> 
> Jim Weirich wrote:
> > On Nov 12, 2007, at 12:09 PM, Berger, Daniel wrote:
> >> Looks like Time#== always returns nil when compared against an 
> >> invalid type. All the other Comparable operators return an 
> ArgumentError:
> > I don't think it should ever be an error to ask if an 
> object is equal 
> > to any other object.  Nil (or false) would be the correct 
> response in 
> > the example you gave.

> not all Comparable operators: the funny thing is that 
> Time.now <=> 0 returns nil, too...I would expect it to throw 
> an error. but "" <=> :foo and 4.3 <=> // also return nil, so 
> I guess it's by design.

Yes, it does indeed appear to be the way <=> is designed in compar.c:

static VALUE
cmp_eq(a)
    VALUE *a;
{
    VALUE c = rb_funcall(a[0], cmp, 1, a[1]);

    if (NIL_P(c)) return Qnil; /* <--- HERE */
    if (rb_cmpint(c, a[0], a[1]) == 0) return Qtrue;
    return Qfalse;
}

I'm not really sure why compar.c does this, though, instead of returning
false.

Regards,

Dan


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