Re: Revision to set-based interval literals
Folk
On 5 Mar 2015, at 10:20, Vincent Lefevre <vincent@xxxxxxxxxx> wrote:
> On 2015-03-05 11:17:18 +0100, Vincent Lefevre wrote:
>> On 2015-03-04 16:15:30 +0000, John Pryce wrote:
>>> Comments please on this fairly drastic shortening of §12.11
>>> "Interval and number literals". It needs to be read alongside the
>>> new §9.4, which Dmitry will be revising, or maybe has already.
>>
>> I'm wondering whether interval literals should be specified mainly
>> at Level 1 instead of Level 2. The new §12.11.1 says: "This subclause
>> extends the specifications of 9.4" but §9.4 in mainly about Level 1,
>> and when one writes "[1.234e5,Inf]", this first designates a Level 1
>> interval.
>
> I initially thought that Level 2 was OK because a string is the
> same datum at Level 1 and Level 2. However the interpretation as
> a literal depends on the level, and one normally first considers
> the interpretation at Level 1.
I thought about this a lot when we first did (set based) interval literals, and eventually decided to put them into Level 2. I think the old text in 12.11 does make it clear what notions are Level 1. However, I will look at it more broadly and see if the new, shorter, 12.11 should be part of Level 1. BTW I put the latter in the repository, r436.
John Pryce