Mike Meyer wrote: > This version includes the input from various and sundry people. Thanks > to everyone who contributed. > > <mike > > PEP: XXX > Title: A rational number module for Python ... > Implicit Construction > --------------------- > > When combined with a floating type - either complex or float - or a > decimal type, the result will be a TypeError. The reason for this is > that floating point numbers - including complex - and decimals are > already imprecise. To convert them to rational would give an > incorrect impression that the results of the operation are > precise. The proper way to add a rational to one of these types is to > convert the rational to that type explicitly before doing the > operation.
I disagree with raising a TypeError here. If, in mixed-type expressions, we treat ints as a special case of rationals, it's inconsistent for rationals to raise TypeErrors in situations where int doesn't. >>> 2 + 0.5 2.5 >>> Rational(2) + 0.5 TypeError: unsupported operand types for +: 'Rational' and 'float' -- http://mail.python.org/mailman/listinfo/python-list
