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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
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Subject: Re: What is the history behind Natural'First = 0 ?
Date: Fri, 1 May 2020 12:13:12 +0200
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On 5/1/20 6:51 AM, reinert wrote:
> 
> There is no consensus about including 0 among the natural numbers.

Precisely, so Ichbiah was free to use Natural for whichever definition he 
considered best. There was a need for subtypes with lower bounds of 0 and 1, and 
those subtypes needed names, and Ichbiah chose Natural and Positive for them. 
This seems like a good choice; if Natural is used for the latter, I cannot think 
of a decent name for the former (Non_Negative? Natural_Plus_Zero?). Given the 
obvious alternative name Positive for the subtype beginning with 1, it seems 
pragmatic to use Natural for the subtype beginning with 0.

IIRC, Natural and Positive existed in Ada 80.

> Is the key point here: "the standard ISO 80000-2" ?

I doubt it, since that standard didn't exist in 1980.

-- 
Jeff Carter
"Why, the Mayflower was full of Fireflies, and a few
horseflies, too. The Fireflies were on the upper deck,
and the horseflies were on the Fireflies."
Duck Soup
95