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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.os.vms
Subject: Re: basic BASIC question
Date: Sun, 2 Feb 2025 00:35:48 -0000 (UTC)
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On Fri, 31 Jan 2025 10:18:00 -0500, Arne Vajhøj wrote:

> Is it common to use:
> 
> declare integer constant TRUE = -1
> declare integer constant FALSE = 0
> 
> 
> ?

I can remember on the Motorola 68000, false was 0 (all bits clear) and 
true was -1 (all bits set). Being a Pascal fan at the time, I thought this 
was really a bad idea. In Pascal you have the equivalant of

    type
        boolean = (false, true);

so false clearly maps to 0 and true to 1.

Why is it important to insist on this? So that you can use boolean, like 
any other discrete type, as an array index type. E.g.

    var
        double_buffer : array [boolean] of buffer;
        thisbuf : boolean;

Glad to see that C99 sort-of agrees with Pascal. Certainly it says the 
only *defined* values of bool type are 0 for false and 1 for true.