Re: Multidimensional array vs. array of array

[Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>]

lutz@iks-jena.de (Lutz Donnerhacke) writes:

> How does a skilled Ada programmer define a return type containing a
> multidimensional array? 

I suspect the answer is : you don't. Define a procedure with an 'in
out' parameter instead. Or one 'in' and one 'out'.

> Of course, the simple solution works:
> 
>   type Equations is array (Rows range <>, Columns range <>) of Number;
>   type Workspace (row : Rows; col : Columns) is record
>     eqs : Equations (Rows'First .. row, Columns'First .. col);
>     ... some more stuff ...
>   end record;
>   function Init_Workspace return Workspace;
> 
> But this approach fails miserably on extracting a single row from the result
> as well as on construction the result in a recursive function.

Yes, this is a fundamental limitation. If you think about a reasonable
implementaion of multi-dimensional arrays, and what you are asking the
compiler to do, it will make sense that it is a limitation.

-- 
-- Stephe