Re: Constructors motion 30 Version 2: small amendment
Vincent
On 7 Feb 2012, at 15:24, Vincent Lefevre wrote:
>> A NaI by definition is a decorated interval value that can never be
>> the result of a successful construction, and is used to signal a
>> construction failure. What NaI values exist will be decided by a
>> later motion on decorations, but there must be at least one.
>
> Isn't NaI a Level 2+ notion only?
I entirely disagree. What is the point of
- defining decorations at Level 1;
- saying that only decorated-interval constructors exist;
- being able to define decorated-interval values -- such as (Empty, ill)
in my current system -- that can be used for the desired diagnostic
purpose, i.e. as NaI values;
if you then relegate NaI to Level 2+?
What I would consider reasonable is to have just one generic NaI at Level 1, which could be refined to several values (TBD) at Level 2+. Rather like we often talk of a generic "NaN", ignoring the fact that it can take many values via its payload.
John P