This topic seems to be of more general interest, given the discussions we've been having regarding the evaluation of 0^0.
When we were writing up the specification of ODF 1.2's OpenFormula we had the goal to describe how real-world spreadsheet applications worked today. Where they worked the same then we wrote up in detail how they worked. Where there was variance among implementations then we tried to describe the bounds within which current applications behaved. So our work was mainly descriptive. There is not a stick big enough to force (at that time) Sun, Microsoft, IBM, Google as well as Gnumeric and KSpread (now Calligra) to change their implementations. This lead to a series of behaviors which were specified to be "implementation-defined", or in some case "locale-defined" or "unspecified". These are subtly different, and express nuances common in standards, what we refer to as "dimensions of variability". The W3C has a note on the topic: http://www.w3.org/TR/spec-variability/ But essentially, standardizers try to strike a balance between interoperability and cost to implement a standard. Even with physical standards, say for a screw or a bolt, there are tolerances give. The screw must have a length of 3cm +/- 0.1mm, for example. If the tolerance were set much higher then the cost to conform would skyrocket, but the incremental interop benefits would diminish. So the art of standardization the art of finding the right balance. This is political also, so it is also in the realm of the "art of the possible" in any given time and place. So.... when putting together OpenFormula I created a spreadsheet to collect together the 61 implementation-defined or unspecified behaviors in OpenFormula. If any is really interested in this area I'd recommend reviewing this spreadsheet. It is a lot easier/faster than reading the ODF 1.2 specification: http://markmail.org/thread/iz2gggmwednmchqe If we ever do go to a warning mode in Calc, where users are warned about potential calculation issues, these would probably be ones that we would check for. Regards, -Rob
