Re: Constructors motion
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