[Python-Dev] Mixing float and Decimal -- thread reboot (original) (raw)

Paul Moore p.f.moore at gmail.com
Mon Mar 22 21:45:05 CET 2010

On 22 March 2010 19:32, Mark Dickinson <dickinsm at gmail.com> wrote:

I think getting this to work would involve a lot of extra code and significant 'cleverness'.  I'd prefer the simple-to-implement and simple-to-explain option of rounding the Fraction before performing the operation, even if this means that the whole operation involves two rounding operations.  It's not so different from what currently happens for Fraction+float, or even int+float.

My instinct throughout this discussion has been that

a_decimal + a_fraction

is in effect

a_decimal + a_fraction.numerator / a_fraction.denominator

and as the numerator and denomination can be converted into exact decimals, my instincts "expect" a double rounding. Anything else effectively means implementing partial cases of (a+b/c) treated as a ternary operation.

So I guess I'm +1 on Mark's suggestion. Paul.

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