[Python-checkins] python/dist/src/Objects listobject.c,2.134,2.135

[Raymond Hettinger]

I think they added the three-way if tests to handle cases where
an object instance defined a rich comparison operator and
returned something other than -1, 0, or 1.  At one time, I
think 2 and/or -2 had a meaning.  But then, I could be confusing
it with another story.

----- Original Message ----- 
From: "Neal Norwitz" <neal@metaslash.com>
To: <rhettinger@users.sourceforge.net>
Sent: Thursday, September 05, 2002 10:53 AM
Subject: Re: [Python-checkins] python/dist/src/Objects listobject.c,2.134,2.135


> rhettinger@users.sourceforge.net wrote:
> > 
> >   list_contains(PyListObject *a, PyObject *el)
> >   {
> > !       int i, cmp;
> > 
> > !       for (i = 0, cmp = 0 ; cmp == 0 && i < a->ob_size; ++i)
> > !               cmp = PyObject_RichCompareBool(el, PyList_GET_ITEM(a, i),
> >                                                    Py_EQ);
> > !       if (cmp > 0)
> > !               return 1;
> > !       if (cmp < 0)
> > !               return -1;
> >         return 0;
> >   }
> 
> PyObject_RichCompareBool() returns the correct value:
> /* Return -1 if error; 1 if v op w; 0 if not (v op w). */
> 
> So you could do:
> 
> for (...)
> cmp = PyObject_RichCompareBool(...);
> return cmp;
> 
> Neal