marlowsd at gmail.com
Tue Oct 23 11:36:59 CEST 2012
On 22/10/2012 19:15, Ashley Yakeley wrote:
> On 22.10.2012 11:05, Johan Tibell wrote:
>>> I think it's OK if a compiler accepts a program incorrectly marked
>>> "Rank2Types" when it actually requires rank-n types?
>> It's an interesting question: does Rank2Types mean "I require at least
>> rank-2 types" or "I only use rank-2 types"?
> I think it means "I require at least rank-2 types".
> To clarify, I think it's OK if a compiler accepts a program marked
> "Rank2Types" and incorrectly not marked "RankNTypes" when it actually
> requires rank-n types.
I don't think I understand why you would want an extension flag to mean
"at least" rather than "at most". No other extension flag works that
way. If you take that view to its logical conclusion, we would never
need to specify any extension flags at all.
Rank2Types is only useful if it really means rank-2 types, which it
apparently doesn't, so I'm quite happy to deprecate it. We don't have
to actually remove it for a long time, since the cost of maintaining one
flag that is a synonym for another flag is small.
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