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From: amado.alves@gmail.com
Newsgroups: comp.lang.ada
Subject: Re: Larger matrices
Date: Fri, 8 Aug 2008 02:59:56 -0700 (PDT)
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Date: 2008-08-08T02:59:56-07:00
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> > And Ada got in the way: slicing restricted to one-dimensional arrays!
>
> Compared to other languages that have no slicing at all?

There are languages better than Ada at array indexing, including
slicing. If there aren't, there should be!

A bidimensional array like the standard Real_Matrix should be
compatible with a unidimensional array like Real_Vector.
One row (or one column) of a matrix is a vector.
In fact aggregate notation reflects this

Matrix := ( (a, b, c) ,
            (d, e, f) ,
            (g, h, i) );

Vector := (x, y, x);

but then the obvious are illegal:

Vector := Matrix (1); -- (a, b, c)

or

Band_Matrix := Matrix (1 .. 2); -- ( (a, b, c) ,
                                --   (d, e, f) )

A good language should even permit

Vertical_Band_Matrix := Matrix (Matrix'Range, 1 .. 2); -- ( (a, b) ,
                                                            (d, e) ,
                                                       --   (g, h) )
or

Block := Matrix (1 .. 2, 1 .. 2); -- ( (a, b) ,
                                  --   (d, e) )