Re: More on flavor conversions (was:Re: Revised FlavorsText)
John Pryce replied to:
>On 2014 Mar 18, at 09:57, Hossam A. H. Fahmy wrote:
>> I agree with George. The text seems to be well written
>> and covers the intended purpose.
>> George wrote:
>>> Sounds OK to me.
Sorry to spoil the party, but I disagree (not with the "well written"
part, but with the underlying intended purpose).
> Grand. What about the "which flavor is in force" aspect, i.e. is conversion
> an import or an export function? I still feel import is more natural.
Yes, Import and Export is the right way to think about this. But we are
strirring up a hornet's nest if we want actual conversion operations,
which require full knowledge and understanding of BOTH flavors. That
seems an unreasonable burden to me.
Earlier, John wrote:
> - If there's no way of converting, it's just several disjoint
> implementations so what's the point?
That's precisely the point: one standard that provides for the
possibility of several disjoint implementations that do however
agree on a large and important common subset.
> - The implementation must document what conversion *means* mathematically,
> hence for what intervals it succeeds at Level 1: which includes common
> intervals.
The implementation must also provide this documentation for its interchange
types, and THAT's how I would expect two flavors to cooperate: The F1 and
F2 programs exchange data through import and export of interchange types.
For common intervals this completely solves the problem. For others the
Import function may give a failure indication (some non-common intervals
may still be convertible, e.g. if both flavors support unbounded intervals).
This DOES assume that there will be no gratuitous differences between the
interchange formats of the two flavors, e.g. different representations for
decorations that substantially denote the same quality. Perhaps it was a
mistake to place interchange formats entirely in the flavor-specific chapter
-- but given the lack of a sufficiently worked out alternative flavor, it is
not easy to tease out the common notions.
Michel.
---Sent: 2014-03-18 14:03:33 UTC