[omniORB] native python fixed point in omniORBpy

[Luke Deller]

Hi,

Are there any plans to deprecate omnipyFixed in favour of
decimal.Decimal (which has been in the standard library since Python 2.4
released in 2004)?

I realise that such a change would deviate from the Python language
mapping. It seems to me though that the Python language mapping is so
far out of date that it no longer conforms to the CORBA requirements for
language mappings:
the CORBA 2.6 spec says in 3.10.3.4: "the fixed data type will be mapped
to the native fixed point capability of a programming language, if
available".

Strictly speaking decimal.Decimal is a floating-point type rather than a
fixed-point type because the scale can be modified by arithmetic
operations. This is also true for omnipyFixed. I suspect that this
does match what the CORBA specification intended for the "fixed-point"
type though, because this floating-point behaviour for arithmetic is
explicitly defined for evaluation of IDL constant expressions in section
3.9.2 of the CORBA 2.6 spec.

Regards,
Luke.

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[Duncan Grisby]

Post by Luke Deller
Are there any plans to deprecate omnipyFixed in favour of
decimal.Decimal (which has been in the standard library since Python 2.4
released in 2004)?

I don't have any plans to do it, but if somebody submitted a patch, that
might encourage the plans... ;-)

Post by Luke Deller
I realise that such a change would deviate from the Python language
mapping. It seems to me though that the Python language mapping is so
far out of date that it no longer conforms to the CORBA requirements for
the CORBA 2.6 spec says in 3.10.3.4: "the fixed data type will be mapped
to the native fixed point capability of a programming language, if
available".

I think it could be done in a way that's compatible with the CORBA
mapping. I haven't looked into the details, though.

Post by Luke Deller
Strictly speaking decimal.Decimal is a floating-point type rather than a
fixed-point type because the scale can be modified by arithmetic
operations. This is also true for omnipyFixed. I suspect that this
does match what the CORBA specification intended for the "fixed-point"
type though, because this floating-point behaviour for arithmetic is
explicitly defined for evaluation of IDL constant expressions in section
3.9.2 of the CORBA 2.6 spec.

As we've talked about already, CORBA.fixed is a floating-point type, so
decimal.Decimal is the right kind of beast.

Cheers,

Duncan.