On Fri, Apr 2, 2010 at 2:38 AM, Mark Dickinson <dicki...@gmail.com> wrote: > On Mon, Mar 22, 2010 at 7:52 PM, Guido van Rossum <gu...@python.org> wrote: >> On Mon, Mar 22, 2010 at 11:36 AM, Raymond Hettinger >> <raymond.hettin...@gmail.com> wrote: >>> One other thought. >>> >>> The Decimal constructor should now accept floats as a possible input type. >>> Formerly, we separated that out to Decimal.from_float() because >>> decimals weren't interoperable with floats. >> >> Not sure this follows; Fraction(1.1) raises an exception, you have to >> use Fraction.from_float(). > > Is there any good reason for this, other than a parallel with Decimal? > It seems to me that Raymond's arguments for allowing direct > construction of a Decimal from a float apply equally well to the > Fraction type. > > If we're going to allow Decimal(1.1), I'd like to allow Fraction(1.1) > to succeed as well (giving the equivalent of > Fraction.from_float(1.1)). > > The main argument against allowing this (for both Fraction and > Decimal) seems to be that the result of Decimal(1.1) or Fraction(1.1) > could be confusing. But it's an immediate, explicit confusion, which > can be quickly resolved by pointing the confusee to the section on > floating-point in the appendix, so I don't find this objection > particularly compelling.
Agreed. If people don't learn about from_float() they might do weird stuff like Decimal(0) + 1.1. Making Fraction and Decimal do the same thing should be easy enough. -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
