Re: Unconstrained Arrays

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

belteshazzar wrote:
> I have a program that uses a lot of different sized arrays and passed
> into math functions. So I'm using an unconstrained array type. The
> problem that I have is that I'm not allowed to use "new" this means
> that I have to use pools (which I can't because to intantiate a pool I
> have to constrain the array type) or allocated the arrays on the
> stack. Allocating the arrays on the stack is fine, BUT it means that i
> have to use array initializers so that they remain unconstrained
> rather than becoming an anonomous contrained type that can no longer
> be passed to my math functions.

I'm not clear what you're talking about. You can pass a constrained subtype to a 
subprogram that takes a parameter of an unconstrained array type.

For example, String is an unconstrained array type. If we have

function F (S : in String) return Natural;

V : String (1 .. 10);
C : Natural;

then it's perfectly legal to call F with V as its actual parameter:

C := F (S);

> Also, and the main point of my post, I've found that I can place the
> unconstrained array inside a record with a distriminant and this seems
> to solve all our problems. We don't have to use array initialisers and
> we can get pointers to aliased objects that can be easily passed to
> the math functions.

Here is your problem. There should be no reason to pass explicit pointers to 
these functions. Your best solution is to rewrite or change your library.

-- 
Jeff Carter
"Drown in a vat of whiskey. Death, where is thy sting?"
Never Give a Sucker an Even Break
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