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From: "Jerry" <lanceboyle@qwest.net>
Newsgroups: comp.lang.ada
Subject: Re: Why does this work? (overloads)
Date: 7 Feb 2007 12:53:43 -0800
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Date: 2007-02-07T12:53:43-08:00
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Jeffrey R. Carter wrote:
> Jerry wrote:
> > (1) Why does the following work?
>
> Because Ada was designed so you can do this.
>
> > (2) Have I done something stupid or dangerous?
>
> No.
>
Excellent. I knew there was some reason that I was using Ada ;).
>
> > -- Some declarations...
> > f, x, H : Real_Vector(0 .. NN - 1);
>
> Note that in mathematics, matrices and vectors are indexed from 1. 1 ..
> NN also avoids the common error of forgetting the "- 1".
>
Yes, but  time series are usually indexed from 0. Sometimes, the FFT
of a time series is indexed from 0 and sometimes -NN/2 .. NN/2-1. When
one uses a time series in a vector or matrix, conundrums obviously
arise, not only in computer code but in print. I once figured out how
to make Pascal let me have it both ways by declaring both types, one
type indexed 0..NN-1 and the other 1..NN, and then I set a pointer of
one type to an array originally declared with another type. I'm
guessing that Ada doesn't allow this, however.

> Because the context of overload resolution for "+" (ARM 8.6) doesn't
> allow this if there is another interpretation that isn't an error.

Thanks for the great explanation.

Jerry