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Re: Constructors motion

George (et al),

Isn't "not-an-interval" the operator version of an "exception," at
least in the sense of IEEE since the original 754?

Along these lines, my personal view is that it is OK (if other
considerations warrant it) to have "not an interval" in level 1,
since "not an interval" is a logical mathematical statement.

Baker

On 12/3/2011 5:41 AM, Corliss, George wrote:

On Dec 3, 2011, at 3:12 AM, John Pryce wrote:


P1788 members

In the next day or two I expect to circulate to you, after the Officers have had a chance to comment, a draft of most of the description of Level 1 (omitting the decorations material and some lesser items), asking you to vote for its acceptance as standard text.

. . .



I have a query however. When a constructor call "fails", should the call
(a) return Empty, as currently written;
(b) return a "Not an Interval" value, which must then exist at Level 1; or
(c) not return any value, i.e. the function is simply undefined at this input argument?

E.g. text2interval("rubbish").


Hmmm.  Good question.

I THINK that at the LANGUAGE level, I'd like to raise an exception so I cannot ignore the error.  But that's not THIS standard.

Plan B: "Not an Interval".  Empty is a valid interval, so returning Empty is a lie.  However, I understand your hesitation to introduce "Not an Interval" at level 1.

I will listen with interest to the views of others.

Dr. George F. Corliss
Electrical and Computer Engineering
Marquette University
P.O. Box 1881
1515 W. Wisconsin Ave
Milwaukee WI 53201-1881 USA
414-288-6599; GasDay: 288-4400; Fax 288-5579
George.Corliss@xxxxxxxxxxxxx
www.eng.mu.edu/corlissg




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