[Python-Dev] Re: Re: Decimal type question [Prothon] (original) (raw)

Mark Hahn mark at prothon.org
Wed Aug 11 20:53:21 CEST 2004

Michael Chermside wrote:

Mark Hahn writes:

I am more interested now in hearing about people's feelings on the idea of having the Decimal type "in-between" Int and Float. Assume a decent Decimal implementation is used. All right. I think that "in-between" Int and Float is a bad idea -- or at least that it's a bad way to think about a decent design. "in-between" suggests that Float has greater range than Decimal which has greater range than Int... but in your design that simply isn't true. Your Int, for instance, can represent values that neither Decimal nor Float can handle.

What do you think of the newer idea of using the IBM floating decimal for all numerics? Tim Peters and others pushed this on me.

Performance would be handled somewhat by automatically switching between ints, bigints, and decimal internally, but with no loss of precision except when a divide or other such operation happens. I would still have a hardware based binary floating point type that you have to manually specify if you want hardware performance for floats.

I am thinking of having all current constant formats default to the "Decimal" type (0, 123, 123.456, 123e3) and have a new constant type using the letter 'f' for the binary "Float" type (0f0, 123f0, 123.456f0, 123.f3).

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